class Sequel::Dataset
A dataset represents an SQL query. Datasets can be used to select, insert, update and delete records.
Query results are always retrieved on demand, so a dataset can be kept around and reused indefinitely (datasets never cache results):
my_posts = DB[:posts].where(author: 'david') # no records are retrieved my_posts.all # records are retrieved my_posts.all # records are retrieved again
Datasets are frozen and use a functional style where modification methods return modified copies of the the dataset. This allows you to reuse datasets:
posts = DB[:posts] davids_posts = posts.where(author: 'david') old_posts = posts.where{stamp < Date.today - 7} davids_old_posts = davids_posts.where{stamp < Date.today - 7}
Datasets are Enumerable objects, so they can be manipulated using many of the Enumerable methods, such as map and inject. Note that there are some methods that Dataset defines that override methods defined in Enumerable and result in different behavior, such as select and group_by.
For more information, see the “Dataset Basics” guide.
Constants
- OPTS
- TRUE_FREEZE
-
Whether
Dataset#freezecan actually freeze datasets. True only on ruby 2.4+, as it requires clone(freeze: false)
1 - Methods that return modified datasets
↑ topConstants
- COLUMN_CHANGE_OPTS
-
The dataset options that require the removal of cached columns if changed.
- CONDITIONED_JOIN_TYPES
-
These symbols have _join methods created (e.g. inner_join) that call
join_tablewith the symbol, passing along the arguments and block from the method call. - EMPTY_ARRAY
- EXTENSIONS
-
Hashof extension name symbols to callable objects to load the extension into theDatasetobject (usually by extending it with a module defined in the extension). - EXTENSION_MODULES
-
Hashof extension name symbols to modules to load to implement the extension. - JOIN_METHODS
-
All methods that return modified datasets with a joined table added.
- NON_SQL_OPTIONS
-
Which options don’t affect the
SQLgeneration. Used by simple_select_all? to determine if this is a simple SELECT * FROM table. - PAREN_WRAPPER
- QUERY_METHODS
-
Methods that return modified datasets
- SIMPLE_SELECT_ALL_ALLOWED_FROM
-
From types allowed to be considered a simple_select_all
- UNCONDITIONED_JOIN_TYPES
-
These symbols have _join methods created (e.g. natural_join). They accept a table argument and options hash which is passed to
join_table, and they raise an error if called with a block.
Public Class Methods
Source
# File lib/sequel/dataset/query.rb 55 def self.register_extension(ext, mod=nil, &block) 56 if mod 57 raise(Error, "cannot provide both mod and block to Dataset.register_extension") if block 58 if mod.is_a?(Module) 59 block = proc{|ds| ds.extend(mod)} 60 Sequel::Database.register_extension(ext){|db| db.extend_datasets(mod)} 61 Sequel.synchronize{EXTENSION_MODULES[ext] = mod} 62 else 63 block = mod 64 end 65 end 66 67 unless mod.is_a?(Module) 68 Sequel::Deprecation.deprecate("Providing a block or non-module to Sequel::Dataset.register_extension is deprecated and support for it will be removed in Sequel 6.") 69 end 70 71 Sequel.synchronize{EXTENSIONS[ext] = block} 72 end
Register an extension callback for Dataset objects. ext should be the extension name symbol, and mod should be a Module that will be included in the dataset’s class. This also registers a Database extension that will extend all of the database’s datasets.
Public Instance Methods
Save original clone implementation, as some other methods need to call it internally.
Source
# File lib/sequel/dataset/query.rb 90 def clone(opts = nil || (return self)) 91 # return self used above because clone is called by almost all 92 # other query methods, and it is the fastest approach 93 c = super(:freeze=>false) 94 c.opts.merge!(opts) 95 unless opts.each_key{|o| break if COLUMN_CHANGE_OPTS.include?(o)} 96 c.clear_columns_cache 97 end 98 c.freeze 99 end
Returns a new clone of the dataset with the given options merged. If the options changed include options in COLUMN_CHANGE_OPTS, the cached columns are deleted. This method should generally not be called directly by user code.
Source
# File lib/sequel/dataset/query.rb 129 def distinct(*args, &block) 130 virtual_row_columns(args, block) 131 if args.empty? 132 return self if opts[:distinct] == EMPTY_ARRAY 133 cached_dataset(:_distinct_ds){clone(:distinct => EMPTY_ARRAY)} 134 else 135 raise(InvalidOperation, "DISTINCT ON not supported") unless supports_distinct_on? 136 clone(:distinct => args.freeze) 137 end 138 end
Returns a copy of the dataset with the SQL DISTINCT clause. The DISTINCT clause is used to remove duplicate rows from the output. If arguments are provided, uses a DISTINCT ON clause, in which case it will only be distinct on those columns, instead of all returned columns. If a block is given, it is treated as a virtual row block, similar to where. Raises an error if arguments are given and DISTINCT ON is not supported.
DB[:items].distinct # SQL: SELECT DISTINCT * FROM items DB[:items].order(:id).distinct(:id) # SQL: SELECT DISTINCT ON (id) * FROM items ORDER BY id DB[:items].order(:id).distinct{func(:id)} # SQL: SELECT DISTINCT ON (func(id)) * FROM items ORDER BY id
There is support for emulating the DISTINCT ON support in MySQL, but it does not support the ORDER of the dataset, and also doesn’t work in many cases if the ONLY_FULL_GROUP_BY sql_mode is used, which is the default on MySQL 5.7.5+.
Source
# File lib/sequel/dataset/query.rb 157 def except(dataset, opts=OPTS) 158 raise(InvalidOperation, "EXCEPT not supported") unless supports_intersect_except? 159 raise(InvalidOperation, "EXCEPT ALL not supported") if opts[:all] && !supports_intersect_except_all? 160 compound_clone(:except, dataset, opts) 161 end
Adds an EXCEPT clause using a second dataset object. An EXCEPT compound dataset returns all rows in the current dataset that are not in the given dataset. Raises an InvalidOperation if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_selfalias - :all
-
Set to true to use EXCEPT ALL instead of EXCEPT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self, use with care.
DB[:items].except(DB[:other_items]) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS t1 DB[:items].except(DB[:other_items], all: true, from_self: false) # SELECT * FROM items EXCEPT ALL SELECT * FROM other_items DB[:items].except(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items EXCEPT SELECT * FROM other_items) AS i
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# File lib/sequel/dataset/query.rb 187 def exclude(*cond, &block) 188 add_filter(:where, cond, true, &block) 189 end
Performs the inverse of Dataset#where. Note that if you have multiple filter conditions, this is not the same as a negation of all conditions.
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software') DB[:items].exclude(category: 'software', id: 3) # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
Also note that SQL uses 3-valued boolean logic (true, false, NULL), so the inverse of a true condition is a false condition, and will still not match rows that were NULL originally. If you take the earlier example:
DB[:items].exclude(category: 'software') # SELECT * FROM items WHERE (category != 'software')
Note that this does not match rows where category is NULL. This is because NULL is an unknown value, and you do not know whether or not the NULL category is software. You can explicitly specify how to handle NULL values if you want:
DB[:items].exclude(Sequel.~(category: nil) & {category: 'software'}) # SELECT * FROM items WHERE ((category IS NULL) OR (category != 'software'))
Source
# File lib/sequel/dataset/query.rb 198 def exclude_having(*cond, &block) 199 add_filter(:having, cond, true, &block) 200 end
Inverts the given conditions and adds them to the HAVING clause.
DB[:items].select_group(:name).exclude_having{count(name) < 2} # SELECT name FROM items GROUP BY name HAVING (count(name) >= 2)
See documentation for exclude for how inversion is handled in regards to SQL 3-valued boolean logic.
Source
# File lib/sequel/dataset/query.rb 206 def extension(*exts) 207 exts.each{|ext| Sequel.extension(ext) unless Sequel.synchronize{EXTENSIONS[ext]}} 208 mods = exts.map{|ext| Sequel.synchronize{EXTENSION_MODULES[ext]}} 209 if mods.all? 210 with_extend(*mods) 211 else 212 with_extend(DeprecatedSingletonClassMethods).extension(*exts) 213 end 214 end
Return a clone of the dataset loaded with the given dataset extensions. If no related extension file exists or the extension does not have specific support for Dataset objects, an error will be raised.
Source
# File lib/sequel/dataset/query.rb 226 def filter(*cond, &block) 227 where(*cond, &block) 228 end
Alias for where.
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# File lib/sequel/dataset/query.rb 233 def for_update 234 cached_lock_style_dataset(:_for_update_ds, :update) 235 end
Returns a cloned dataset with a :update lock style.
DB[:table].for_update # SELECT * FROM table FOR UPDATE
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# File lib/sequel/dataset/query.rb 246 def from(*source, &block) 247 virtual_row_columns(source, block) 248 table_alias_num = 0 249 ctes = nil 250 source.map! do |s| 251 case s 252 when Dataset 253 if hoist_cte?(s) 254 ctes ||= [] 255 ctes += s.opts[:with] 256 s = s.clone(:with=>nil) 257 end 258 SQL::AliasedExpression.new(s, dataset_alias(table_alias_num+=1)) 259 when Symbol 260 sch, table, aliaz = split_symbol(s) 261 if aliaz 262 s = sch ? SQL::QualifiedIdentifier.new(sch, table) : SQL::Identifier.new(table) 263 SQL::AliasedExpression.new(s, aliaz.to_sym) 264 else 265 s 266 end 267 else 268 s 269 end 270 end 271 o = {:from=>source.empty? ? nil : source.freeze} 272 o[:with] = ((opts[:with] || EMPTY_ARRAY) + ctes).freeze if ctes 273 o[:num_dataset_sources] = table_alias_num if table_alias_num > 0 274 clone(o) 275 end
Returns a copy of the dataset with the source changed. If no source is given, removes all tables. If multiple sources are given, it is the same as using a CROSS JOIN (cartesian product) between all tables. If a block is given, it is treated as a virtual row block, similar to where.
DB[:items].from # SQL: SELECT * DB[:items].from(:blah) # SQL: SELECT * FROM blah DB[:items].from(:blah, :foo) # SQL: SELECT * FROM blah, foo DB[:items].from{fun(arg)} # SQL: SELECT * FROM fun(arg)
Source
# File lib/sequel/dataset/query.rb 294 def from_self(opts=OPTS) 295 fs = {} 296 @opts.keys.each{|k| fs[k] = nil unless non_sql_option?(k)} 297 pr = proc do 298 c = clone(fs).from(opts[:alias] ? as(opts[:alias], opts[:column_aliases]) : self) 299 if cols = _columns 300 c.send(:columns=, cols) 301 end 302 c 303 end 304 305 opts.empty? ? cached_dataset(:_from_self_ds, &pr) : pr.call 306 end
Returns a dataset selecting from the current dataset. Options:
- :alias
-
Controls the alias of the table
- :column_aliases
-
Also aliases columns, using derived column lists. Only used in conjunction with :alias.
ds = DB[:items].order(:name).select(:id, :name) # SELECT id,name FROM items ORDER BY name ds.from_self # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS t1 ds.from_self(alias: :foo) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo ds.from_self(alias: :foo, column_aliases: [:c1, :c2]) # SELECT * FROM (SELECT id, name FROM items ORDER BY name) AS foo(c1, c2)
Source
# File lib/sequel/dataset/query.rb 343 def grep(columns, patterns, opts=OPTS) 344 column_op = opts[:all_columns] ? :AND : :OR 345 if opts[:all_patterns] 346 conds = Array(patterns).map do |pat| 347 SQL::BooleanExpression.new(column_op, *Array(columns).map{|c| SQL::StringExpression.like(c, pat, opts)}) 348 end 349 where(SQL::BooleanExpression.new(:AND, *conds)) 350 else 351 conds = Array(columns).map do |c| 352 SQL::BooleanExpression.new(:OR, *Array(patterns).map{|pat| SQL::StringExpression.like(c, pat, opts)}) 353 end 354 where(SQL::BooleanExpression.new(column_op, *conds)) 355 end 356 end
Match any of the columns to any of the patterns. The terms can be strings (which use LIKE) or regular expressions if the database supports that. Note that the total number of pattern matches will be Array(columns).length * Array(terms).length, which could cause performance issues.
Options (all are boolean):
- :all_columns
-
All columns must be matched to any of the given patterns.
- :all_patterns
-
All patterns must match at least one of the columns.
- :case_insensitive
-
Use a case insensitive pattern match (the default is case sensitive if the database supports it).
If both :all_columns and :all_patterns are true, all columns must match all patterns.
Examples:
dataset.grep(:a, '%test%') # SELECT * FROM items WHERE (a LIKE '%test%' ESCAPE '\') dataset.grep([:a, :b], %w'%test% foo') # SELECT * FROM items WHERE ((a LIKE '%test%' ESCAPE '\') OR (a LIKE 'foo' ESCAPE '\') # OR (b LIKE '%test%' ESCAPE '\') OR (b LIKE 'foo' ESCAPE '\')) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (b LIKE '%foo%' ESCAPE '\')) # AND ((a LIKE '%bar%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_columns: true) # SELECT * FROM a WHERE (((a LIKE '%foo%' ESCAPE '\') OR (a LIKE '%bar%' ESCAPE '\')) # AND ((b LIKE '%foo%' ESCAPE '\') OR (b LIKE '%bar%' ESCAPE '\'))) dataset.grep([:a, :b], %w'%foo% %bar%', all_patterns: true, all_columns: true) # SELECT * FROM a WHERE ((a LIKE '%foo%' ESCAPE '\') AND (b LIKE '%foo%' ESCAPE '\') # AND (a LIKE '%bar%' ESCAPE '\') AND (b LIKE '%bar%' ESCAPE '\'))
Source
# File lib/sequel/dataset/query.rb 365 def group(*columns, &block) 366 virtual_row_columns(columns, block) 367 clone(:group => (columns.compact.empty? ? nil : columns.freeze)) 368 end
Returns a copy of the dataset with the results grouped by the value of the given columns. If a block is given, it is treated as a virtual row block, similar to where.
DB[:items].group(:id) # SELECT * FROM items GROUP BY id DB[:items].group(:id, :name) # SELECT * FROM items GROUP BY id, name DB[:items].group{[a, sum(b)]} # SELECT * FROM items GROUP BY a, sum(b)
Source
# File lib/sequel/dataset/query.rb 396 def group_and_count(*columns, &block) 397 select_group(*columns, &block).select_append(COUNT_OF_ALL_AS_COUNT) 398 end
Returns a dataset grouped by the given column with count by group. Column aliases may be supplied, and will be included in the select clause. If a block is given, it is treated as a virtual row block, similar to where.
Examples:
DB[:items].group_and_count(:name).all # SELECT name, count(*) AS count FROM items GROUP BY name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count(:first_name, :last_name).all # SELECT first_name, last_name, count(*) AS count FROM items GROUP BY first_name, last_name # => [{:first_name=>'a', :last_name=>'b', :count=>1}, ...] DB[:items].group_and_count(Sequel[:first_name].as(:name)).all # SELECT first_name AS name, count(*) AS count FROM items GROUP BY first_name # => [{:name=>'a', :count=>1}, ...] DB[:items].group_and_count{substr(:first_name, 1, 1).as(:initial)}.all # SELECT substr(first_name, 1, 1) AS initial, count(*) AS count FROM items GROUP BY substr(first_name, 1, 1) # => [{:initial=>'a', :count=>1}, ...]
Source
# File lib/sequel/dataset/query.rb 406 def group_append(*columns, &block) 407 columns = @opts[:group] + columns if @opts[:group] 408 group(*columns, &block) 409 end
Returns a copy of the dataset with the given columns added to the list of existing columns to group on. If no existing columns are present this method simply sets the columns as the initial ones to group on.
DB[:items].group_append(:b) # SELECT * FROM items GROUP BY b DB[:items].group(:a).group_append(:b) # SELECT * FROM items GROUP BY a, b
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# File lib/sequel/dataset/query.rb 371 def group_by(*columns, &block) 372 group(*columns, &block) 373 end
Alias of group
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# File lib/sequel/dataset/query.rb 412 def group_cube 413 raise Error, "GROUP BY CUBE not supported on #{db.database_type}" unless supports_group_cube? 414 clone(:group_options=>:cube) 415 end
Adds the appropriate CUBE syntax to GROUP BY.
Source
# File lib/sequel/dataset/query.rb 418 def group_rollup 419 raise Error, "GROUP BY ROLLUP not supported on #{db.database_type}" unless supports_group_rollup? 420 clone(:group_options=>:rollup) 421 end
Adds the appropriate ROLLUP syntax to GROUP BY.
Source
# File lib/sequel/dataset/query.rb 424 def grouping_sets 425 raise Error, "GROUP BY GROUPING SETS not supported on #{db.database_type}" unless supports_grouping_sets? 426 clone(:group_options=>:"grouping sets") 427 end
Adds the appropriate GROUPING SETS syntax to GROUP BY.
Source
# File lib/sequel/dataset/query.rb 433 def having(*cond, &block) 434 add_filter(:having, cond, &block) 435 end
Returns a copy of the dataset with the HAVING conditions changed. See where for argument types.
DB[:items].group(:sum).having(sum: 10) # SELECT * FROM items GROUP BY sum HAVING (sum = 10)
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# File lib/sequel/dataset/query.rb 454 def intersect(dataset, opts=OPTS) 455 raise(InvalidOperation, "INTERSECT not supported") unless supports_intersect_except? 456 raise(InvalidOperation, "INTERSECT ALL not supported") if opts[:all] && !supports_intersect_except_all? 457 compound_clone(:intersect, dataset, opts) 458 end
Adds an INTERSECT clause using a second dataset object. An INTERSECT compound dataset returns all rows in both the current dataset and the given dataset. Raises an InvalidOperation if the operation is not supported. Options:
- :alias
-
Use the given value as the
from_selfalias - :all
-
Set to true to use INTERSECT ALL instead of INTERSECT, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self, use with care.
DB[:items].intersect(DB[:other_items]) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS t1 DB[:items].intersect(DB[:other_items], all: true, from_self: false) # SELECT * FROM items INTERSECT ALL SELECT * FROM other_items DB[:items].intersect(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items INTERSECT SELECT * FROM other_items) AS i
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# File lib/sequel/dataset/query.rb 471 def invert 472 cached_dataset(:_invert_ds) do 473 having, where = @opts.values_at(:having, :where) 474 if having.nil? && where.nil? 475 where(false) 476 else 477 o = {} 478 o[:having] = SQL::BooleanExpression.invert(having) if having 479 o[:where] = SQL::BooleanExpression.invert(where) if where 480 clone(o) 481 end 482 end 483 end
Inverts the current WHERE and HAVING clauses. If there is neither a WHERE or HAVING clause, adds a WHERE clause that is always false.
DB[:items].where(category: 'software').invert # SELECT * FROM items WHERE (category != 'software') DB[:items].where(category: 'software', id: 3).invert # SELECT * FROM items WHERE ((category != 'software') OR (id != 3))
See documentation for exclude for how inversion is handled in regards to SQL 3-valued boolean logic.
Source
# File lib/sequel/dataset/query.rb 486 def join(*args, &block) 487 inner_join(*args, &block) 488 end
Alias of inner_join
Source
# File lib/sequel/dataset/query.rb 550 def join_table(type, table, expr=nil, options=OPTS, &block) 551 if hoist_cte?(table) 552 s, ds = hoist_cte(table) 553 return s.join_table(type, ds, expr, options, &block) 554 end 555 556 using_join = options[:join_using] || (expr.is_a?(Array) && !expr.empty? && expr.all?{|x| x.is_a?(Symbol)}) 557 if using_join && !supports_join_using? 558 h = {} 559 expr.each{|e| h[e] = e} 560 return join_table(type, table, h, options) 561 end 562 563 table_alias = options[:table_alias] 564 565 if table.is_a?(SQL::AliasedExpression) 566 table_expr = if table_alias 567 SQL::AliasedExpression.new(table.expression, table_alias, table.columns) 568 else 569 table 570 end 571 table = table_expr.expression 572 table_name = table_alias = table_expr.alias 573 elsif table.is_a?(Dataset) 574 if table_alias.nil? 575 table_alias_num = (@opts[:num_dataset_sources] || 0) + 1 576 table_alias = dataset_alias(table_alias_num) 577 end 578 table_name = table_alias 579 table_expr = SQL::AliasedExpression.new(table, table_alias) 580 else 581 table, implicit_table_alias = split_alias(table) 582 table_alias ||= implicit_table_alias 583 table_name = table_alias || table 584 table_expr = table_alias ? SQL::AliasedExpression.new(table, table_alias) : table 585 end 586 587 join = if expr.nil? and !block 588 SQL::JoinClause.new(type, table_expr) 589 elsif using_join 590 raise(Sequel::Error, "can't use a block if providing an array of symbols as expr") if block 591 SQL::JoinUsingClause.new(expr, type, table_expr) 592 else 593 last_alias = options[:implicit_qualifier] || @opts[:last_joined_table] || first_source_alias 594 qualify_type = options[:qualify] 595 if Sequel.condition_specifier?(expr) 596 expr = expr.map do |k, v| 597 qualify_type = default_join_table_qualification if qualify_type.nil? 598 case qualify_type 599 when false 600 nil # Do no qualification 601 when :deep 602 k = Sequel::Qualifier.new(table_name).transform(k) 603 v = Sequel::Qualifier.new(last_alias).transform(v) 604 else 605 k = qualified_column_name(k, table_name) if k.is_a?(Symbol) 606 v = qualified_column_name(v, last_alias) if v.is_a?(Symbol) 607 end 608 [k,v] 609 end 610 expr = SQL::BooleanExpression.from_value_pairs(expr) 611 end 612 if block 613 expr2 = yield(table_name, last_alias, @opts[:join] || EMPTY_ARRAY) 614 expr = expr ? SQL::BooleanExpression.new(:AND, expr, expr2) : expr2 615 end 616 SQL::JoinOnClause.new(expr, type, table_expr) 617 end 618 619 opts = {:join => ((@opts[:join] || EMPTY_ARRAY) + [join]).freeze} 620 opts[:last_joined_table] = table_name unless options[:reset_implicit_qualifier] == false 621 opts[:num_dataset_sources] = table_alias_num if table_alias_num 622 clone(opts) 623 end
Returns a joined dataset. Not usually called directly, users should use the appropriate join method (e.g. join, left_join, natural_join, cross_join) which fills in the type argument.
Takes the following arguments:
- type
-
The type of join to do (e.g. :inner)
- table
-
table to join into the current dataset. Generally one of the following types:
String,Symbol-
identifier used as table or view name
Dataset-
a subselect is performed with an alias of tN for some value of N
SQL::Function-
set returning function
SQL::AliasedExpression-
already aliased expression. Uses given alias unless overridden by the :table_alias option.
- expr
-
conditions used when joining, depends on type:
Hash,Arrayof pairs-
Assumes key (1st arg) is column of joined table (unless already qualified), and value (2nd arg) is column of the last joined or primary table (or the :implicit_qualifier option). To specify multiple conditions on a single joined table column, you must use an array. Uses a JOIN with an ON clause.
Array-
If all members of the array are symbols, considers them as columns and uses a JOIN with a USING clause. Most databases will remove duplicate columns from the result set if this is used.
- nil
-
If a block is not given, doesn’t use ON or USING, so the JOIN should be a NATURAL or CROSS join. If a block is given, uses an ON clause based on the block, see below.
- otherwise
-
Treats the argument as a filter expression, so strings are considered literal, symbols specify boolean columns, and
Sequelexpressions can be used. Uses a JOIN with an ON clause.
- options
-
a hash of options, with the following keys supported:
- :table_alias
-
Override the table alias used when joining. In general you shouldn’t use this option, you should provide the appropriate
SQL::AliasedExpressionas the table argument. - :implicit_qualifier
-
The name to use for qualifying implicit conditions. By default, the last joined or primary table is used.
- :join_using
-
Force the using of JOIN USING, even if
expris not an array of symbols. - :reset_implicit_qualifier
-
Can set to false to ignore this join when future joins determine qualifier for implicit conditions.
- :qualify
-
Can be set to false to not do any implicit qualification. Can be set to :deep to use the
QualifierAST Transformer, which will attempt to qualify subexpressions of the expression tree. Can be set to :symbol to only qualify symbols. Defaults to the value of default_join_table_qualification.
- block
-
The block argument should only be given if a JOIN with an ON clause is used, in which case it yields the table alias/name for the table currently being joined, the table alias/name for the last joined (or first table), and an array of previous
SQL::JoinClause. Unlikewhere, this block is not treated as a virtual row block.
Examples:
DB[:a].join_table(:cross, :b) # SELECT * FROM a CROSS JOIN b DB[:a].join_table(:inner, DB[:b], c: d) # SELECT * FROM a INNER JOIN (SELECT * FROM b) AS t1 ON (t1.c = a.d) DB[:a].join_table(:left, Sequel[:b].as(:c), [:d]) # SELECT * FROM a LEFT JOIN b AS c USING (d) DB[:a].natural_join(:b).join_table(:inner, :c) do |ta, jta, js| (Sequel.qualify(ta, :d) > Sequel.qualify(jta, :e)) & {Sequel.qualify(ta, :f)=>DB.from(js.first.table).select(:g)} end # SELECT * FROM a NATURAL JOIN b INNER JOIN c # ON ((c.d > b.e) AND (c.f IN (SELECT g FROM b)))
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# File lib/sequel/dataset/query.rb 644 def lateral 645 return self if opts[:lateral] 646 cached_dataset(:_lateral_ds){clone(:lateral=>true)} 647 end
Marks this dataset as a lateral dataset. If used in another dataset’s FROM or JOIN clauses, it will surround the subquery with LATERAL to enable it to deal with previous tables in the query:
DB.from(:a, DB[:b].where(Sequel[:a][:c]=>Sequel[:b][:d]).lateral) # SELECT * FROM a, LATERAL (SELECT * FROM b WHERE (a.c = b.d))
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# File lib/sequel/dataset/query.rb 659 def limit(l, o = (no_offset = true; nil)) 660 return from_self.limit(l, o) if @opts[:sql] 661 662 if l.is_a?(Range) 663 no_offset = false 664 o = l.first 665 l = l.last - l.first + (l.exclude_end? ? 0 : 1) 666 end 667 l = l.to_i if l.is_a?(String) && !l.is_a?(LiteralString) 668 if l.is_a?(Integer) 669 raise(Error, 'Limits must be greater than or equal to 1') unless l >= 1 670 end 671 672 ds = clone(:limit=>l) 673 ds = ds.offset(o) unless no_offset 674 ds 675 end
If given an integer, the dataset will contain only the first l results. If given a range, it will contain only those at offsets within that range. If a second argument is given, it is used as an offset. To use an offset without a limit, pass nil as the first argument.
DB[:items].limit(10) # SELECT * FROM items LIMIT 10 DB[:items].limit(10, 20) # SELECT * FROM items LIMIT 10 OFFSET 20 DB[:items].limit(10...20) # SELECT * FROM items LIMIT 10 OFFSET 10 DB[:items].limit(10..20) # SELECT * FROM items LIMIT 11 OFFSET 10 DB[:items].limit(nil, 20) # SELECT * FROM items OFFSET 20
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# File lib/sequel/dataset/query.rb 689 def lock_style(style) 690 clone(:lock => style) 691 end
Returns a cloned dataset with the given lock style. If style is a string, it will be used directly. You should never pass a string to this method that is derived from user input, as that can lead to SQL injection.
A symbol may be used for database independent locking behavior, but all supported symbols have separate methods (e.g. for_update).
DB[:items].lock_style('FOR SHARE NOWAIT') # SELECT * FROM items FOR SHARE NOWAIT DB[:items].lock_style('FOR UPDATE OF table1 SKIP LOCKED') # SELECT * FROM items FOR UPDATE OF table1 SKIP LOCKED
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# File lib/sequel/dataset/query.rb 702 def merge_delete(&block) 703 _merge_when(:type=>:delete, &block) 704 end
Return a dataset with a WHEN MATCHED THEN DELETE clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.
merge_delete # WHEN MATCHED THEN DELETE merge_delete{a > 30} # WHEN MATCHED AND (a > 30) THEN DELETE
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# File lib/sequel/dataset/query.rb 718 def merge_insert(*values, &block) 719 _merge_when(:type=>:insert, :values=>values, &block) 720 end
Return a dataset with a WHEN NOT MATCHED THEN INSERT clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.
The arguments provided can be any arguments that would be accepted by insert.
merge_insert(i1: :i2, a: Sequel[:b]+11) # WHEN NOT MATCHED THEN INSERT (i1, a) VALUES (i2, (b + 11)) merge_insert(:i2, Sequel[:b]+11){a > 30} # WHEN NOT MATCHED AND (a > 30) THEN INSERT VALUES (i2, (b + 11))
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# File lib/sequel/dataset/query.rb 731 def merge_update(values, &block) 732 _merge_when(:type=>:update, :values=>values, &block) 733 end
Return a dataset with a WHEN MATCHED THEN UPDATE clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.
merge_update(i1: Sequel[:i1]+:i2+10, a: Sequel[:a]+:b+20) # WHEN MATCHED THEN UPDATE SET i1 = (i1 + i2 + 10), a = (a + b + 20) merge_update(i1: :i2){a > 30} # WHEN MATCHED AND (a > 30) THEN UPDATE SET i1 = i2
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# File lib/sequel/dataset/query.rb 739 def merge_using(source, join_condition) 740 clone(:merge_using => [source, join_condition].freeze) 741 end
Return a dataset with the source and join condition to use for the MERGE statement.
merge_using(:m2, i1: :i2) # USING m2 ON (i1 = i2)
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# File lib/sequel/dataset/query.rb 748 def naked 749 return self unless opts[:row_proc] 750 cached_dataset(:_naked_ds){with_row_proc(nil)} 751 end
Returns a cloned dataset without a row_proc.
ds = DB[:items].with_row_proc(:invert.to_proc) ds.all # => [{2=>:id}] ds.naked.all # => [{:id=>2}]
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# File lib/sequel/dataset/query.rb 758 def nowait 759 return self if opts[:nowait] 760 cached_dataset(:_nowait_ds) do 761 raise(Error, 'This dataset does not support raises errors instead of waiting for locked rows') unless supports_nowait? 762 clone(:nowait=>true) 763 end 764 end
Returns a copy of the dataset that will raise a DatabaseLockTimeout instead of waiting for rows that are locked by another transaction
DB[:items].for_update.nowait # SELECT * FROM items FOR UPDATE NOWAIT
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# File lib/sequel/dataset/query.rb 771 def offset(o) 772 o = o.to_i if o.is_a?(String) && !o.is_a?(LiteralString) 773 if o.is_a?(Integer) 774 raise(Error, 'Offsets must be greater than or equal to 0') unless o >= 0 775 end 776 clone(:offset => o) 777 end
Returns a copy of the dataset with a specified order. Can be safely combined with limit. If you call limit with an offset, it will override the offset if you’ve called offset first.
DB[:items].offset(10) # SELECT * FROM items OFFSET 10
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# File lib/sequel/dataset/query.rb 785 def or(*cond, &block) 786 if @opts[:where].nil? 787 self 788 else 789 add_filter(:where, cond, false, :OR, &block) 790 end 791 end
Adds an alternate filter to an existing WHERE clause using OR. If there is no WHERE clause, then the default is WHERE true, and OR would be redundant, so return the dataset in that case.
DB[:items].where(:a).or(:b) # SELECT * FROM items WHERE a OR b DB[:items].or(:b) # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 807 def order(*columns, &block) 808 virtual_row_columns(columns, block) 809 clone(:order => (columns.compact.empty?) ? nil : columns.freeze) 810 end
Returns a copy of the dataset with the order changed. If the dataset has an existing order, it is ignored and overwritten with this order. If a nil is given the returned dataset has no order. This can accept multiple arguments of varying kinds, such as SQL functions. If a block is given, it is treated as a virtual row block, similar to where.
DB[:items].order(:name) # SELECT * FROM items ORDER BY name DB[:items].order(:a, :b) # SELECT * FROM items ORDER BY a, b DB[:items].order(Sequel.lit('a + b')) # SELECT * FROM items ORDER BY a + b DB[:items].order(Sequel[:a] + :b) # SELECT * FROM items ORDER BY (a + b) DB[:items].order(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name DESC DB[:items].order(Sequel.asc(:name, nulls: :last)) # SELECT * FROM items ORDER BY name ASC NULLS LAST DB[:items].order{sum(name).desc} # SELECT * FROM items ORDER BY sum(name) DESC DB[:items].order(nil) # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 817 def order_append(*columns, &block) 818 columns = @opts[:order] + columns if @opts[:order] 819 order(*columns, &block) 820 end
Returns a copy of the dataset with the order columns added to the end of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_append(:b) # SELECT * FROM items ORDER BY a, b
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# File lib/sequel/dataset/query.rb 823 def order_by(*columns, &block) 824 order(*columns, &block) 825 end
Alias of order
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# File lib/sequel/dataset/query.rb 828 def order_more(*columns, &block) 829 order_append(*columns, &block) 830 end
Alias of order_append.
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# File lib/sequel/dataset/query.rb 837 def order_prepend(*columns, &block) 838 ds = order(*columns, &block) 839 @opts[:order] ? ds.order_append(*@opts[:order]) : ds 840 end
Returns a copy of the dataset with the order columns added to the beginning of the existing order.
DB[:items].order(:a).order(:b) # SELECT * FROM items ORDER BY b DB[:items].order(:a).order_prepend(:b) # SELECT * FROM items ORDER BY b, a
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# File lib/sequel/dataset/query.rb 849 def qualify(table=(cache=true; first_source)) 850 o = @opts 851 return self if o[:sql] 852 853 pr = proc do 854 h = {} 855 (o.keys & QUALIFY_KEYS).each do |k| 856 h[k] = qualified_expression(o[k], table) 857 end 858 h[:select] = [SQL::ColumnAll.new(table)].freeze if !o[:select] || o[:select].empty? 859 clone(h) 860 end 861 862 cache ? cached_dataset(:_qualify_ds, &pr) : pr.call 863 end
Qualify to the given table, or first source if no table is given.
DB[:items].where(id: 1).qualify # SELECT items.* FROM items WHERE (items.id = 1) DB[:items].where(id: 1).qualify(:i) # SELECT i.* FROM items WHERE (i.id = 1)
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# File lib/sequel/dataset/query.rb 883 def returning(*values) 884 if values.empty? 885 return self if opts[:returning] == EMPTY_ARRAY 886 cached_dataset(:_returning_ds) do 887 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 888 clone(:returning=>EMPTY_ARRAY) 889 end 890 else 891 raise Error, "RETURNING is not supported on #{db.database_type}" unless supports_returning?(:insert) 892 clone(:returning=>values.freeze) 893 end 894 end
Modify the RETURNING clause, only supported on a few databases. If returning is used, instead of insert returning the autogenerated primary key or update/delete returning the number of modified rows, results are returned using fetch_rows.
DB[:items].returning # RETURNING * DB[:items].returning(nil) # RETURNING NULL DB[:items].returning(:id, :name) # RETURNING id, name DB[:items].returning.insert(a: 1) do |hash| # hash for each row inserted, with values for all columns end DB[:items].returning.update(a: 1) do |hash| # hash for each row updated, with values for all columns end DB[:items].returning.delete(a: 1) do |hash| # hash for each row deleted, with values for all columns end
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# File lib/sequel/dataset/query.rb 903 def reverse(*order, &block) 904 if order.empty? && !block 905 cached_dataset(:_reverse_ds){order(*invert_order(@opts[:order]))} 906 else 907 virtual_row_columns(order, block) 908 order(*invert_order(order.empty? ? @opts[:order] : order.freeze)) 909 end 910 end
Returns a copy of the dataset with the order reversed. If no order is given, the existing order is inverted.
DB[:items].reverse(:id) # SELECT * FROM items ORDER BY id DESC DB[:items].reverse{foo(bar)} # SELECT * FROM items ORDER BY foo(bar) DESC DB[:items].order(:id).reverse # SELECT * FROM items ORDER BY id DESC DB[:items].order(:id).reverse(Sequel.desc(:name)) # SELECT * FROM items ORDER BY name ASC
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# File lib/sequel/dataset/query.rb 913 def reverse_order(*order, &block) 914 reverse(*order, &block) 915 end
Alias of reverse
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# File lib/sequel/dataset/query.rb 924 def select(*columns, &block) 925 virtual_row_columns(columns, block) 926 clone(:select => columns.freeze) 927 end
Returns a copy of the dataset with the columns selected changed to the given columns. This also takes a virtual row block, similar to where.
DB[:items].select(:a) # SELECT a FROM items DB[:items].select(:a, :b) # SELECT a, b FROM items DB[:items].select{[a, sum(b)]} # SELECT a, sum(b) FROM items
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# File lib/sequel/dataset/query.rb 936 def select_all(*tables) 937 if tables.empty? 938 return self unless opts[:select] 939 cached_dataset(:_select_all_ds){clone(:select => nil)} 940 else 941 select(*tables.map{|t| i, a = split_alias(t); a || i}.map!{|t| SQL::ColumnAll.new(t)}.freeze) 942 end 943 end
Returns a copy of the dataset selecting the wildcard if no arguments are given. If arguments are given, treat them as tables and select all columns (using the wildcard) from each table.
DB[:items].select(:a).select_all # SELECT * FROM items DB[:items].select_all(:items) # SELECT items.* FROM items DB[:items].select_all(:items, :foo) # SELECT items.*, foo.* FROM items
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# File lib/sequel/dataset/query.rb 952 def select_append(*columns, &block) 953 virtual_row_columns(columns, block) 954 select(*(_current_select(true) + columns)) 955 end
Returns a copy of the dataset with the given columns added to the existing selected columns. If no columns are currently selected, it will select the columns given in addition to *.
DB[:items].select(:a).select(:b) # SELECT b FROM items DB[:items].select(:a).select_append(:b) # SELECT a, b FROM items DB[:items].select_append(:b) # SELECT *, b FROM items
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# File lib/sequel/dataset/query.rb 966 def select_group(*columns, &block) 967 virtual_row_columns(columns, block) 968 select(*columns).group(*columns.map{|c| unaliased_identifier(c)}) 969 end
Set both the select and group clauses with the given columns. Column aliases may be supplied, and will be included in the select clause. This also takes a virtual row block similar to where.
DB[:items].select_group(:a, :b) # SELECT a, b FROM items GROUP BY a, b DB[:items].select_group(Sequel[:c].as(:a)){f(c2)} # SELECT c AS a, f(c2) FROM items GROUP BY c, f(c2)
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# File lib/sequel/dataset/query.rb 972 def select_more(*columns, &block) 973 select_append(*columns, &block) 974 end
Alias for select_append.
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# File lib/sequel/dataset/query.rb 983 def select_prepend(*columns, &block) 984 virtual_row_columns(columns, block) 985 select(*(columns + _current_select(false))) 986 end
Returns a copy of the dataset with the given columns added to the existing selected columns. If no columns are currently selected, it will select the columns given in addition to *.
DB[:items].select(:a).select(:b) # SELECT b FROM items DB[:items].select(:a).select_prepend(:b) # SELECT b, a FROM items DB[:items].select_prepend(:b) # SELECT b, * FROM items
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# File lib/sequel/dataset/query.rb 997 def server(servr) 998 clone(:server=>servr) 999 end
Set the server for this dataset to use. Used to pick a specific database shard to run a query against, or to override the default (where SELECT uses :read_only database and all other queries use the :default database). This method is always available but is only useful when database sharding is being used.
DB[:items].all # Uses the :read_only or :default server DB[:items].delete # Uses the :default server DB[:items].server(:blah).delete # Uses the :blah server
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# File lib/sequel/dataset/query.rb 1004 def server?(server) 1005 if db.sharded? && !opts[:server] 1006 server(server) 1007 else 1008 self 1009 end 1010 end
If the database uses sharding and the current dataset has not had a server set, return a cloned dataset that uses the given server. Otherwise, return the receiver directly instead of returning a clone.
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# File lib/sequel/dataset/query.rb 1013 def skip_limit_check 1014 return self if opts[:skip_limit_check] 1015 cached_dataset(:_skip_limit_check_ds) do 1016 clone(:skip_limit_check=>true) 1017 end 1018 end
Specify that the check for limits/offsets when updating/deleting be skipped for the dataset.
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# File lib/sequel/dataset/query.rb 1021 def skip_locked 1022 return self if opts[:skip_locked] 1023 cached_dataset(:_skip_locked_ds) do 1024 raise(Error, 'This dataset does not support skipping locked rows') unless supports_skip_locked? 1025 clone(:skip_locked=>true) 1026 end 1027 end
Skip locked rows when returning results from this dataset.
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# File lib/sequel/dataset/query.rb 1033 def unfiltered 1034 return self unless opts[:where] || opts[:having] 1035 cached_dataset(:_unfiltered_ds){clone(:where => nil, :having => nil)} 1036 end
Returns a copy of the dataset with no filters (HAVING or WHERE clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).unfiltered # SELECT * FROM items GROUP BY a
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# File lib/sequel/dataset/query.rb 1042 def ungrouped 1043 return self unless opts[:group] || opts[:having] 1044 cached_dataset(:_ungrouped_ds){clone(:group => nil, :having => nil)} 1045 end
Returns a copy of the dataset with no grouping (GROUP or HAVING clause) applied.
DB[:items].group(:a).having(a: 1).where(:b).ungrouped # SELECT * FROM items WHERE b
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# File lib/sequel/dataset/query.rb 1063 def union(dataset, opts=OPTS) 1064 compound_clone(:union, dataset, opts) 1065 end
Adds a UNION clause using a second dataset object. A UNION compound dataset returns all rows in either the current dataset or the given dataset. Options:
- :alias
-
Use the given value as the
from_selfalias - :all
-
Set to true to use UNION ALL instead of UNION, so duplicate rows can occur
- :from_self
-
Set to false to not wrap the returned dataset in a
from_self, use with care.
DB[:items].union(DB[:other_items]) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS t1 DB[:items].union(DB[:other_items], all: true, from_self: false) # SELECT * FROM items UNION ALL SELECT * FROM other_items DB[:items].union(DB[:other_items], alias: :i) # SELECT * FROM (SELECT * FROM items UNION SELECT * FROM other_items) AS i
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# File lib/sequel/dataset/query.rb 1070 def unlimited 1071 return self unless opts[:limit] || opts[:offset] 1072 cached_dataset(:_unlimited_ds){clone(:limit=>nil, :offset=>nil)} 1073 end
Returns a copy of the dataset with no limit or offset.
DB[:items].limit(10, 20).unlimited # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 1078 def unordered 1079 return self unless opts[:order] 1080 cached_dataset(:_unordered_ds){clone(:order=>nil)} 1081 end
Returns a copy of the dataset with no order.
DB[:items].order(:a).unordered # SELECT * FROM items
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# File lib/sequel/dataset/query.rb 1125 def where(*cond, &block) 1126 add_filter(:where, cond, &block) 1127 end
Returns a copy of the dataset with the given WHERE conditions imposed upon it.
Accepts the following argument types:
Hash,Arrayof pairs-
list of equality/inclusion expressions
Symbol-
taken as a boolean column argument (e.g. WHERE active)
Sequel::SQL::BooleanExpression,Sequel::LiteralString-
an existing condition expression, probably created using the
Sequelexpression filter DSL.
where also accepts a block, which should return one of the above argument types, and is treated the same way. This block yields a virtual row object, which is easy to use to create identifiers and functions. For more details on the virtual row support, see the “Virtual Rows” guide
If both a block and regular argument are provided, they get ANDed together.
Examples:
DB[:items].where(id: 3) # SELECT * FROM items WHERE (id = 3) DB[:items].where(Sequel.lit('price < ?', 100)) # SELECT * FROM items WHERE price < 100 DB[:items].where([[:id, [1,2,3]], [:id, 0..10]]) # SELECT * FROM items WHERE ((id IN (1, 2, 3)) AND ((id >= 0) AND (id <= 10))) DB[:items].where(Sequel.lit('price < 100')) # SELECT * FROM items WHERE price < 100 DB[:items].where(:active) # SELECT * FROM items WHERE :active DB[:items].where{price < 100} # SELECT * FROM items WHERE (price < 100)
Multiple where calls can be chained for scoping:
software = dataset.where(category: 'software').where{price < 100} # SELECT * FROM items WHERE ((category = 'software') AND (price < 100))
See the “Dataset Filtering” guide for more examples and details.
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# File lib/sequel/dataset/query.rb 1135 def window(name, opts) 1136 clone(:window=>((@opts[:window]||EMPTY_ARRAY) + [[name, SQL::Window.new(opts)].freeze]).freeze) 1137 end
Return a clone of the dataset with an addition named window that can be referenced in window functions. See Sequel::SQL::Window for a list of options that can be passed in. Example:
DB[:items].window(:w, partition: :c1, order: :c2) # SELECT * FROM items WINDOW w AS (PARTITION BY c1 ORDER BY c2)
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# File lib/sequel/dataset/query.rb 1150 def with(name, dataset, opts=OPTS) 1151 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1152 if hoist_cte?(dataset) 1153 s, ds = hoist_cte(dataset) 1154 s.with(name, ds, opts) 1155 else 1156 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:name=>name, :dataset=>dataset)]).freeze) 1157 end 1158 end
Add a common table expression (CTE) with the given name and a dataset that defines the CTE. A common table expression acts as an inline view for the query.
Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :recursive
-
Specify that this is a recursive CTE
- :materialized
-
Set to false to force inlining of the CTE, or true to force not inlining the CTE (PostgreSQL 12+/SQLite 3.35+).
DB[:items].with(:items, DB[:syx].where(Sequel[:name].like('A%'))) # WITH items AS (SELECT * FROM syx WHERE (name LIKE 'A%' ESCAPE '\')) SELECT * FROM items
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# File lib/sequel/dataset/query.rb 1239 def with_extend(*mods, &block) 1240 c = Sequel.set_temp_name(Class.new(self.class)){"Sequel::Dataset::_Subclass"} 1241 c.include(*mods) unless mods.empty? 1242 c.include(Sequel.set_temp_name(DatasetModule.new(&block)){"Sequel::Dataset::_DatasetModule(#{block.source_location[0,2].join(':')})"}) if block 1243 o = c.freeze.allocate 1244 o.instance_variable_set(:@db, @db) 1245 o.instance_variable_set(:@opts, @opts) 1246 o.instance_variable_set(:@cache, {}) 1247 if cols = cache_get(:_columns) 1248 o.send(:columns=, cols) 1249 end 1250 o.freeze 1251 end
Create a subclass of the receiver’s class, and include the given modules into it. If a block is provided, a DatasetModule is created using the block and is included into the subclass. Create an instance of the subclass using the same db and opts, so that the returned dataset operates similarly to a clone extended with the given modules. This approach is used to avoid singleton classes, which significantly improves performance.
Note that like Object#extend, when multiple modules are provided as arguments the subclass includes the modules in reverse order.
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# File lib/sequel/dataset/query.rb 1216 def with_recursive(name, nonrecursive, recursive, opts=OPTS) 1217 raise(Error, 'This dataset does not support common table expressions') unless supports_cte? 1218 if hoist_cte?(nonrecursive) 1219 s, ds = hoist_cte(nonrecursive) 1220 s.with_recursive(name, ds, recursive, opts) 1221 elsif hoist_cte?(recursive) 1222 s, ds = hoist_cte(recursive) 1223 s.with_recursive(name, nonrecursive, ds, opts) 1224 else 1225 clone(:with=>((@opts[:with]||EMPTY_ARRAY) + [Hash[opts].merge!(:recursive=>true, :name=>name, :dataset=>nonrecursive.union(recursive, {:all=>opts[:union_all] != false, :from_self=>false}))]).freeze) 1226 end 1227 end
Add a recursive common table expression (CTE) with the given name, a dataset that defines the nonrecursive part of the CTE, and a dataset that defines the recursive part of the CTE.
Options:
- :args
-
Specify the arguments/columns for the CTE, should be an array of symbols.
- :union_all
-
Set to false to use UNION instead of UNION ALL combining the nonrecursive and recursive parts.
PostgreSQL 14+ Options:
- :cycle
-
Stop recursive searching when a cycle is detected. Includes two columns in the result of the CTE, a cycle column indicating whether a cycle was detected for the current row, and a path column for the path traversed to get to the current row. If given, must be a hash with the following keys:
- :columns
-
(required) The column or array of columns to use to detect a cycle. If the value of these columns match columns already traversed, then a cycle is detected, and recursive searching will not traverse beyond the cycle (the CTE will include the row where the cycle was detected).
- :cycle_column
-
The name of the cycle column in the output, defaults to :is_cycle.
- :cycle_value
-
The value of the cycle column in the output if the current row was detected as a cycle, defaults to true.
- :noncycle_value
-
The value of the cycle column in the output if the current row was not detected as a cycle, defaults to false. Only respected if :cycle_value is given.
- :path_column
-
The name of the path column in the output, defaults to :path.
- :search
-
Include an order column in the result of the CTE that allows for breadth or depth first searching. If given, must be a hash with the following keys:
- :by
-
(required) The column or array of columns to search by.
- :order_column
-
The name of the order column in the output, defaults to :ordercol.
- :type
-
Set to :breadth to use breadth-first searching (depth-first searching is the default).
DB[:t].with_recursive(:t, DB[:i1].select(:id, :parent_id).where(parent_id: nil), DB[:i1].join(:t, id: :parent_id).select(Sequel[:i1][:id], Sequel[:i1][:parent_id]), args: [:id, :parent_id]) # WITH RECURSIVE t(id, parent_id) AS ( # SELECT id, parent_id FROM i1 WHERE (parent_id IS NULL) # UNION ALL # SELECT i1.id, i1.parent_id FROM i1 INNER JOIN t ON (t.id = i1.parent_id) # ) SELECT * FROM t DB[:t].with_recursive(:t, DB[:i1].where(parent_id: nil), DB[:i1].join(:t, id: :parent_id).select_all(:i1), search: {by: :id, type: :breadth}, cycle: {columns: :id, cycle_value: 1, noncycle_value: 2}) # WITH RECURSIVE t AS ( # SELECT * FROM i1 WHERE (parent_id IS NULL) # UNION ALL # (SELECT i1.* FROM i1 INNER JOIN t ON (t.id = i1.parent_id)) # ) # SEARCH BREADTH FIRST BY id SET ordercol # CYCLE id SET is_cycle TO 1 DEFAULT 2 USING path # SELECT * FROM t
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# File lib/sequel/dataset/query.rb 1268 def with_row_proc(callable) 1269 clone(:row_proc=>callable) 1270 end
Returns a cloned dataset with the given row_proc.
ds = DB[:items] ds.all # => [{:id=>2}] ds.with_row_proc(:invert.to_proc).all # => [{2=>:id}]
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# File lib/sequel/dataset/query.rb 1302 def with_sql(sql, *args) 1303 if sql.is_a?(Symbol) 1304 sql = public_send(sql, *args).freeze 1305 else 1306 sql = SQL::PlaceholderLiteralString.new(sql, args) unless args.empty? 1307 end 1308 clone(:sql=>sql) 1309 end
Returns a copy of the dataset with the static SQL used. This is useful if you want to keep the same row_proc/graph, but change the SQL used to custom SQL.
DB[:items].with_sql('SELECT * FROM foo') # SELECT * FROM foo
You can use placeholders in your SQL and provide arguments for those placeholders:
DB[:items].with_sql('SELECT ? FROM foo', 1) # SELECT 1 FROM foo
You can also provide a method name and arguments to call to get the SQL:
DB[:items].with_sql(:insert_sql, b: 1) # INSERT INTO items (b) VALUES (1)
Note that datasets that specify custom SQL using this method will generally ignore future dataset methods that modify the SQL used, as specifying custom SQL overrides Sequel’s SQL generator. You should probably limit yourself to the following dataset methods when using this method, or use the implicit_subquery extension:
-
each
-
all
-
single_record(if only one record could be returned) -
single_value(if only one record could be returned, and a single column is selected) -
map
-
delete (if a DELETE statement)
-
update (if an UPDATE statement, with no arguments)
-
insert (if an INSERT statement, with no arguments)
-
truncate (if a TRUNCATE statement, with no arguments)
Protected Instance Methods
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# File lib/sequel/dataset/query.rb 1314 def compound_clone(type, dataset, opts) 1315 if dataset.is_a?(Dataset) && dataset.opts[:with] && !supports_cte_in_compounds? 1316 s, ds = hoist_cte(dataset) 1317 return s.compound_clone(type, ds, opts) 1318 end 1319 ds = compound_from_self.clone(:compounds=>(Array(@opts[:compounds]).map(&:dup) + [[type, dataset.compound_from_self, opts[:all]].freeze]).freeze) 1320 opts[:from_self] == false ? ds : ds.from_self(opts) 1321 end
Add the dataset to the list of compounds
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# File lib/sequel/dataset/query.rb 1324 def options_overlap(opts) 1325 !(@opts.map{|k,v| k unless v.nil?}.compact & opts).empty? 1326 end
Return true if the dataset has a non-nil value for any key in opts.
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# File lib/sequel/dataset/query.rb 1335 def simple_select_all? 1336 return false unless (f = @opts[:from]) && f.length == 1 1337 o = @opts.reject{|k,v| v.nil? || non_sql_option?(k)} 1338 from = f.first 1339 from = from.expression if from.is_a?(SQL::AliasedExpression) 1340 1341 if SIMPLE_SELECT_ALL_ALLOWED_FROM.any?{|x| from.is_a?(x)} 1342 case o.length 1343 when 1 1344 true 1345 when 2 1346 (s = o[:select]) && s.length == 1 && s.first.is_a?(SQL::ColumnAll) 1347 else 1348 false 1349 end 1350 else 1351 false 1352 end 1353 end
Whether this dataset is a simple select from an underlying table, such as:
SELECT * FROM table SELECT table.* FROM table
Private Instance Methods
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# File lib/sequel/dataset/query.rb 1379 def _current_select(allow_plain_wildcard) 1380 cur_sel = @opts[:select] 1381 1382 if !cur_sel || cur_sel.empty? 1383 cur_sel = if allow_plain_wildcard && supports_select_all_and_column? 1384 [WILDCARD].freeze 1385 else 1386 _current_select_column_all 1387 end 1388 elsif !allow_plain_wildcard && cur_sel.include?(WILDCARD) 1389 cur_sel = cur_sel.dup 1390 index = cur_sel.index(WILDCARD) 1391 cur_sel.delete(WILDCARD) 1392 _current_select_column_all.each_with_index do |ca, i| 1393 cur_sel.insert(index+i, ca) 1394 end 1395 cur_sel.freeze 1396 end 1397 1398 cur_sel 1399 end
A frozen array for the currently selected columns.
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# File lib/sequel/dataset/query.rb 1403 def _current_select_column_all 1404 tables = Array(@opts[:from]) + Array(@opts[:join]) 1405 tables.map{|t| i, a = split_alias(t); a || i}.map!{|t| SQL::ColumnAll.new(t)}.freeze 1406 end
An array of SQL::ColumnAll objects for all FROM and JOIN tables. Used for select_append and select_prepend.
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# File lib/sequel/dataset/query.rb 1360 def _extension!(exts) 1361 exts.each do |ext| 1362 unless pr = Sequel.synchronize{EXTENSIONS[ext]} 1363 Sequel.extension(ext) 1364 pr = Sequel.synchronize{EXTENSIONS[ext]} 1365 end 1366 1367 if pr 1368 pr.call(self) 1369 else 1370 raise(Error, "Extension #{ext} does not have specific support handling individual datasets (try: Sequel.extension #{ext.inspect})") 1371 end 1372 end 1373 self 1374 end
Load the extensions into the receiver, without checking if the receiver is frozen.
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# File lib/sequel/dataset/query.rb 1409 def _invert_filter(cond, invert) 1410 if invert 1411 SQL::BooleanExpression.invert(cond) 1412 else 1413 cond 1414 end 1415 end
If invert is true, invert the condition.
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# File lib/sequel/dataset/query.rb 1419 def _merge_when(hash, &block) 1420 hash[:conditions] = Sequel.virtual_row(&block) if block 1421 1422 if merge_when = @opts[:merge_when] 1423 clone(:merge_when => (merge_when.dup << hash.freeze).freeze) 1424 else 1425 clone(:merge_when => [hash.freeze].freeze) 1426 end 1427 end
Append to the current MERGE WHEN clauses. Mutates the hash to add the conditions, if a virtual row block is passed.
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# File lib/sequel/dataset/query.rb 1434 def add_filter(clause, cond, invert=false, combine=:AND, &block) 1435 if cond == EMPTY_ARRAY && !block 1436 raise Error, "must provide an argument to a filtering method if not passing a block" 1437 end 1438 1439 cond = cond.first if cond.size == 1 1440 1441 empty = cond == OPTS || cond == EMPTY_ARRAY 1442 1443 if empty && !block 1444 self 1445 else 1446 if cond == nil 1447 cond = Sequel::NULL 1448 end 1449 if empty && block 1450 cond = nil 1451 end 1452 1453 cond = _invert_filter(filter_expr(cond, &block), invert) 1454 cond = SQL::BooleanExpression.new(combine, @opts[clause], cond) if @opts[clause] 1455 1456 if cond.nil? 1457 cond = Sequel::NULL 1458 end 1459 1460 clone(clause => cond) 1461 end 1462 end
Add the given filter condition. Arguments:
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# File lib/sequel/dataset/query.rb 1469 def cached_lock_style_dataset(key, style) 1470 opts[:lock] == style ? self : cached_dataset(key){lock_style(style)} 1471 end
Internals of for_update and adapter-specific lock methods. Returns receiver if it already uses this lock style, and a cached dataset using the given key otherwise. The key could be derived from the style, but doing so would require allocation, so pass it in as an argument.
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# File lib/sequel/dataset/query.rb 1474 def default_join_table_qualification 1475 :symbol 1476 end
The default :qualify option to use for join tables if one is not specified.
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# File lib/sequel/dataset/query.rb 1552 def default_server 1553 server?(:default) 1554 end
Return self if the dataset already has a server, or a cloned dataset with the default server otherwise.
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# File lib/sequel/dataset/query.rb 1482 def filter_expr(expr = nil, &block) 1483 expr = nil if expr == EMPTY_ARRAY 1484 1485 if block 1486 cond = filter_expr(Sequel.virtual_row(&block)) 1487 cond = SQL::BooleanExpression.new(:AND, filter_expr(expr), cond) if expr 1488 return cond 1489 end 1490 1491 case expr 1492 when Hash 1493 SQL::BooleanExpression.from_value_pairs(expr) 1494 when Array 1495 if Sequel.condition_specifier?(expr) 1496 SQL::BooleanExpression.from_value_pairs(expr) 1497 else 1498 raise Error, "Invalid filter expression: #{expr.inspect}" 1499 end 1500 when LiteralString 1501 SQL::PlaceholderLiteralString.new(PAREN_WRAPPER, [expr]) 1502 when Numeric, SQL::NumericExpression, SQL::StringExpression, Proc, String, Set 1503 raise Error, "Invalid filter expression: #{expr.inspect}" 1504 when TrueClass, FalseClass 1505 if supports_where_true? 1506 SQL::BooleanExpression.new(:NOOP, expr) 1507 elsif expr 1508 SQL::Constants::SQLTRUE 1509 else 1510 SQL::Constants::SQLFALSE 1511 end 1512 when PlaceholderLiteralizer::Argument 1513 expr.transform{|v| filter_expr(v)} 1514 when SQL::PlaceholderLiteralString 1515 expr.with_parens 1516 else 1517 expr 1518 end 1519 end
SQL expression object based on the expr type. See where.
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# File lib/sequel/dataset/query.rb 1524 def hoist_cte(ds) 1525 [clone(:with => ((opts[:with] || EMPTY_ARRAY) + ds.opts[:with]).freeze), ds.clone(:with => nil)] 1526 end
Return two datasets, the first a clone of the receiver with the WITH clause from the given dataset added to it, and the second a clone of the given dataset with the WITH clause removed.
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# File lib/sequel/dataset/query.rb 1529 def hoist_cte?(ds) 1530 ds.is_a?(Dataset) && ds.opts[:with] && !supports_cte_in_subqueries? 1531 end
Whether CTEs need to be hoisted from the given ds into the current ds.
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# File lib/sequel/dataset/query.rb 1538 def invert_order(order) 1539 return unless order 1540 order.map do |f| 1541 case f 1542 when SQL::OrderedExpression 1543 f.invert 1544 else 1545 SQL::OrderedExpression.new(f) 1546 end 1547 end 1548 end
Inverts the given order by breaking it into a list of column references and inverting them.
DB[:items].invert_order([Sequel.desc(:id)]]) #=> [Sequel.asc(:id)] DB[:items].invert_order([:category, Sequel.desc(:price)]) #=> [Sequel.desc(:category), Sequel.asc(:price)]
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# File lib/sequel/dataset/query.rb 1557 def non_sql_option?(key) 1558 NON_SQL_OPTIONS.include?(key) 1559 end
Whether the given option key does not affect the generated SQL.
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# File lib/sequel/dataset/query.rb 1563 def virtual_row_columns(columns, block) 1564 if block 1565 v = Sequel.virtual_row(&block) 1566 if v.is_a?(Array) 1567 columns.concat(v) 1568 else 1569 columns << v 1570 end 1571 end 1572 end
Treat the block as a virtual_row block if not nil and add the resulting columns to the columns array (modifies columns).
2 - Methods that execute code on the database
↑ topConstants
- ACTION_METHODS
-
Action methods defined by
Sequelthat execute code on the database. - COLUMNS_CLONE_OPTIONS
-
The clone options to use when retrieving columns for a dataset.
- COUNT_SELECT
- EMPTY_SELECT
Public Instance Methods
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# File lib/sequel/dataset/actions.rb 29 def <<(arg) 30 insert(arg) 31 self 32 end
Inserts the given argument into the database. Returns self so it can be used safely when chaining:
DB[:items] << {id: 0, name: 'Zero'} << DB[:old_items].select(:id, name)
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# File lib/sequel/dataset/actions.rb 38 def [](*conditions) 39 raise(Error, 'You cannot call Dataset#[] with an integer or with no arguments') if (conditions.length == 1 and conditions.first.is_a?(Integer)) or conditions.length == 0 40 first(*conditions) 41 end
Returns the first record matching the conditions. Examples:
DB[:table][id: 1] # SELECT * FROM table WHERE (id = 1) LIMIT 1 # => {:id=>1}
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# File lib/sequel/dataset/actions.rb 51 def all(&block) 52 _all(block){|a| each{|r| a << r}} 53 end
Returns an array with all records in the dataset. If a block is given, the array is iterated over after all items have been loaded.
DB[:table].all # SELECT * FROM table # => [{:id=>1, ...}, {:id=>2, ...}, ...] # Iterate over all rows in the table DB[:table].all{|row| p row}
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# File lib/sequel/dataset/actions.rb 910 def as_hash(key_column, value_column = nil, opts = OPTS) 911 h = opts[:hash] || {} 912 meth = opts[:all] ? :all : :each 913 if value_column 914 return naked.as_hash(key_column, value_column, opts) if row_proc 915 if value_column.is_a?(Array) 916 if key_column.is_a?(Array) 917 public_send(meth){|r| h[r.values_at(*key_column)] = r.values_at(*value_column)} 918 else 919 public_send(meth){|r| h[r[key_column]] = r.values_at(*value_column)} 920 end 921 else 922 if key_column.is_a?(Array) 923 public_send(meth){|r| h[r.values_at(*key_column)] = r[value_column]} 924 else 925 public_send(meth){|r| h[r[key_column]] = r[value_column]} 926 end 927 end 928 elsif key_column.is_a?(Array) 929 public_send(meth){|r| h[key_column.map{|k| r[k]}] = r} 930 else 931 public_send(meth){|r| h[r[key_column]] = r} 932 end 933 h 934 end
Returns a hash with one column used as key and another used as value. If rows have duplicate values for the key column, the latter row(s) will overwrite the value of the previous row(s). If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].as_hash(:id, :name) # SELECT * FROM table # {1=>'Jim', 2=>'Bob', ...} DB[:table].as_hash(:id) # SELECT * FROM table # {1=>{:id=>1, :name=>'Jim'}, 2=>{:id=>2, :name=>'Bob'}, ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].as_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table # {[1, 3]=>['Jim', 'bo'], [2, 4]=>['Bob', 'be'], ...} DB[:table].as_hash([:id, :name]) # SELECT * FROM table # {[1, 'Jim']=>{:id=>1, :name=>'Jim'}, [2, 'Bob']=>{:id=>2, :name=>'Bob'}, ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
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# File lib/sequel/dataset/actions.rb 65 def as_set(column) 66 return naked.as_set(column) if row_proc 67 68 if column.is_a?(Array) 69 to_set{|r| r.values_at(*column)} 70 else 71 to_set{|r| r[column]} 72 end 73 end
Returns sets for column values for each record in the dataset.
DB[:table].as_set(:id) # SELECT * FROM table # => Set[1, 2, 3, ...]
You can also provide an array of column names, in which case the elements of the returned set are arrays (not sets):
DB[:table].as_set([:id, :name]) # SELECT * FROM table # => Set[[1, 'A'], [2, 'B'], [3, 'C'], ...]
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# File lib/sequel/dataset/actions.rb 82 def avg(arg=(no_arg = true), &block) 83 arg = Sequel.virtual_row(&block) if no_arg 84 _aggregate(:avg, arg) 85 end
Returns the average value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].avg(:number) # SELECT avg(number) FROM table LIMIT 1 # => 3 DB[:table].avg{function(column)} # SELECT avg(function(column)) FROM table LIMIT 1 # => 1
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# File lib/sequel/dataset/actions.rb 96 def columns 97 _columns || columns! 98 end
Returns the columns in the result set in order as an array of symbols. If the columns are currently cached, returns the cached value. Otherwise, a SELECT query is performed to retrieve a single row in order to get the columns.
If you are looking for all columns for a single table and maybe some information about each column (e.g. database type), see Database#schema.
DB[:table].columns # => [:id, :name]
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# File lib/sequel/dataset/actions.rb 105 def columns! 106 ds = clone(COLUMNS_CLONE_OPTIONS) 107 ds.each{break} 108 109 if cols = ds.cache[:_columns] 110 self.columns = cols 111 else 112 [] 113 end 114 end
Ignore any cached column information and perform a query to retrieve a row in order to get the columns.
DB[:table].columns! # => [:id, :name]
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# File lib/sequel/dataset/actions.rb 129 def count(arg=(no_arg=true), &block) 130 if no_arg && !block 131 cached_dataset(:_count_ds) do 132 aggregate_dataset.select(COUNT_SELECT).single_value_ds 133 end.single_value!.to_i 134 else 135 if block 136 if no_arg 137 arg = Sequel.virtual_row(&block) 138 else 139 raise Error, 'cannot provide both argument and block to Dataset#count' 140 end 141 end 142 143 _aggregate(:count, arg) 144 end 145 end
Returns the number of records in the dataset. If an argument is provided, it is used as the argument to count. If a block is provided, it is treated as a virtual row, and the result is used as the argument to count.
DB[:table].count # SELECT count(*) AS count FROM table LIMIT 1 # => 3 DB[:table].count(:column) # SELECT count(column) AS count FROM table LIMIT 1 # => 2 DB[:table].count{foo(column)} # SELECT count(foo(column)) AS count FROM table LIMIT 1 # => 1
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# File lib/sequel/dataset/actions.rb 163 def delete(&block) 164 sql = delete_sql 165 if uses_returning?(:delete) 166 returning_fetch_rows(sql, &block) 167 else 168 execute_dui(sql) 169 end 170 end
Deletes the records in the dataset, returning the number of records deleted.
DB[:table].delete # DELETE * FROM table # => 3
Some databases support using multiple tables in a DELETE query. This requires multiple FROM tables (JOINs can also be used). As multiple FROM tables use an implicit CROSS JOIN, you should make sure your WHERE condition uses the appropriate filters for the FROM tables:
DB.from(:a, :b).join(:c, :d=>Sequel[:b][:e]).where{{a[:f]=>b[:g], a[:id]=>c[:h]}}. delete # DELETE FROM a # USING b # INNER JOIN c ON (c.d = b.e) # WHERE ((a.f = b.g) AND (a.id = c.h))
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# File lib/sequel/dataset/actions.rb 181 def each 182 if rp = row_proc 183 fetch_rows(select_sql){|r| yield rp.call(r)} 184 else 185 fetch_rows(select_sql){|r| yield r} 186 end 187 self 188 end
Iterates over the records in the dataset as they are yielded from the database adapter, and returns self.
DB[:table].each{|row| p row} # SELECT * FROM table
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, you should use all instead of each for the outer queries, or use a separate thread or shard inside each.
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# File lib/sequel/dataset/actions.rb 196 def empty? 197 cached_dataset(:_empty_ds) do 198 (@opts[:sql] ? from_self : self).single_value_ds.unordered.select(EMPTY_SELECT) 199 end.single_value!.nil? 200 end
Returns true if no records exist in the dataset, false otherwise
DB[:table].empty? # SELECT 1 AS one FROM table LIMIT 1 # => false
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# File lib/sequel/dataset/actions.rb 237 def first(*args, &block) 238 case args.length 239 when 0 240 unless block 241 return(@opts[:sql] ? single_record! : single_record) 242 end 243 when 1 244 arg = args[0] 245 if arg.is_a?(Integer) 246 res = if block 247 if loader = cached_placeholder_literalizer(:_first_integer_cond_loader) do |pl| 248 where(pl.arg).limit(pl.arg) 249 end 250 251 loader.all(filter_expr(&block), arg) 252 else 253 where(&block).limit(arg).all 254 end 255 else 256 if loader = cached_placeholder_literalizer(:_first_integer_loader) do |pl| 257 limit(pl.arg) 258 end 259 260 loader.all(arg) 261 else 262 limit(arg).all 263 end 264 end 265 266 return res 267 end 268 where_args = args 269 args = arg 270 end 271 272 if loader = cached_where_placeholder_literalizer(where_args||args, block, :_first_cond_loader) do |pl| 273 _single_record_ds.where(pl.arg) 274 end 275 276 loader.first(filter_expr(args, &block)) 277 else 278 _single_record_ds.where(args, &block).single_record! 279 end 280 end
Returns the first matching record if no arguments are given. If a integer argument is given, it is interpreted as a limit, and then returns all matching records up to that limit. If any other type of argument(s) is passed, it is treated as a filter and the first matching record is returned. If a block is given, it is used to filter the dataset before returning anything.
If there are no records in the dataset, returns nil (or an empty array if an integer argument is given).
Examples:
DB[:table].first # SELECT * FROM table LIMIT 1 # => {:id=>7} DB[:table].first(2) # SELECT * FROM table LIMIT 2 # => [{:id=>6}, {:id=>4}] DB[:table].first(id: 2) # SELECT * FROM table WHERE (id = 2) LIMIT 1 # => {:id=>2} DB[:table].first(Sequel.lit("id = 3")) # SELECT * FROM table WHERE (id = 3) LIMIT 1 # => {:id=>3} DB[:table].first(Sequel.lit("id = ?", 4)) # SELECT * FROM table WHERE (id = 4) LIMIT 1 # => {:id=>4} DB[:table].first{id > 2} # SELECT * FROM table WHERE (id > 2) LIMIT 1 # => {:id=>5} DB[:table].first(Sequel.lit("id > ?", 4)){id < 6} # SELECT * FROM table WHERE ((id > 4) AND (id < 6)) LIMIT 1 # => {:id=>5} DB[:table].first(2){id < 2} # SELECT * FROM table WHERE (id < 2) LIMIT 2 # => [{:id=>1}]
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# File lib/sequel/dataset/actions.rb 284 def first!(*args, &block) 285 first(*args, &block) || raise(Sequel::NoMatchingRow.new(self)) 286 end
Calls first. If first returns nil (signaling that no row matches), raise a Sequel::NoMatchingRow exception.
Source
# File lib/sequel/dataset/actions.rb 312 def get(column=(no_arg=true; nil), &block) 313 ds = naked 314 if block 315 raise(Error, 'Must call Dataset#get with an argument or a block, not both') unless no_arg 316 ds = ds.select(&block) 317 column = ds.opts[:select] 318 column = nil if column.is_a?(Array) && column.length < 2 319 elsif no_arg && opts[:sql] 320 return ds.single_value! 321 else 322 case column 323 when Array 324 ds = ds.select(*column) 325 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 326 if loader = cached_placeholder_literalizer(:_get_loader) do |pl| 327 ds.single_value_ds.select(pl.arg) 328 end 329 330 return loader.get(column) 331 end 332 333 ds = ds.select(column) 334 else 335 if loader = cached_placeholder_literalizer(:_get_alias_loader) do |pl| 336 ds.single_value_ds.select(Sequel.as(pl.arg, :v)) 337 end 338 339 return loader.get(column) 340 end 341 342 ds = ds.select(Sequel.as(column, :v)) 343 end 344 end 345 346 if column.is_a?(Array) 347 if r = ds.single_record 348 r.values_at(*hash_key_symbols(column)) 349 end 350 else 351 ds.single_value 352 end 353 end
Return the column value for the first matching record in the dataset. Raises an error if both an argument and block is given.
DB[:table].get(:id) # SELECT id FROM table LIMIT 1 # => 3 ds.get{sum(id)} # SELECT sum(id) AS v FROM table LIMIT 1 # => 6
You can pass an array of arguments to return multiple arguments, but you must make sure each element in the array has an alias that Sequel can determine:
DB[:table].get([:id, :name]) # SELECT id, name FROM table LIMIT 1 # => [3, 'foo'] DB[:table].get{[sum(id).as(sum), name]} # SELECT sum(id) AS sum, name FROM table LIMIT 1 # => [6, 'foo']
If called on a dataset with raw SQL, returns the first value in the dataset without changing the selection or setting a limit:
DB["SELECT id FROM table"].get # SELECT id FROM table # => 3
Source
# File lib/sequel/dataset/actions.rb 400 def import(columns, values, opts=OPTS) 401 return insert(columns, values) if values.is_a?(Dataset) 402 403 return if values.empty? 404 raise(Error, 'Using Sequel::Dataset#import with an empty column array is not allowed') if columns.empty? 405 ds = opts[:server] ? server(opts[:server]) : self 406 407 if slice_size = opts.fetch(:commit_every, opts.fetch(:slice, default_import_slice)) 408 offset = 0 409 rows = [] 410 while offset < values.length 411 rows << ds._import(columns, values[offset, slice_size], opts) 412 offset += slice_size 413 end 414 rows.flatten 415 else 416 ds._import(columns, values, opts) 417 end 418 end
Inserts multiple records into the associated table. This method can be used to efficiently insert a large number of records into a table in a single query if the database supports it. Inserts are automatically wrapped in a transaction if necessary.
This method is called with a columns array and an array of value arrays:
DB[:table].import([:x, :y], [[1, 2], [3, 4]]) # INSERT INTO table (x, y) VALUES (1, 2) # INSERT INTO table (x, y) VALUES (3, 4)
or, if the database supports it:
# INSERT INTO table (x, y) VALUES (1, 2), (3, 4)
This method also accepts a dataset instead of an array of value arrays:
DB[:table].import([:x, :y], DB[:table2].select(:a, :b)) # INSERT INTO table (x, y) SELECT a, b FROM table2
The return value of this method is undefined and should not be used, except in two cases:
-
When the
return: :primary_keyoption is used. -
On PostgreSQL, when the dataset uses RETURNING. In this case, if a single value is returned per row, the return value is an array of those values. If multiple values are returned per row, the return value is an array of hashes.
Options:
- :commit_every
-
Open a new transaction for every given number of records. For example, if you provide a value of 50, will commit after every 50 records. When a transaction is not required, this option controls the maximum number of values to insert with a single statement; it does not force the use of a transaction.
- :return
-
When this is set to :primary_key, returns an array of autoincremented primary key values for the rows inserted. This does not have an effect if
valuesis aDataset. - :server
-
Set the server/shard to use for the transaction and insert queries.
- :skip_transaction
-
Do not use a transaction even when using multiple INSERT queries.
- :slice
-
Same as :commit_every, :commit_every takes precedence.
Source
# File lib/sequel/dataset/actions.rb 456 def insert(*values, &block) 457 sql = insert_sql(*values) 458 if uses_returning?(:insert) 459 returning_fetch_rows(sql, &block) 460 else 461 execute_insert(sql) 462 end 463 end
Inserts values into the associated table. The returned value is generally the value of the autoincremented primary key for the inserted row, assuming that a single row is inserted and the table has an autoincrementing primary key.
insert handles a number of different argument formats:
- no arguments or single empty hash
-
Uses
DEFAULTVALUES - single hash
-
Most common format, treats keys as columns and values as values
- single array
-
Treats entries as values, with no columns
- two arrays
-
Treats first array as columns, second array as values
- single
Dataset -
Treats as an insert based on a selection from the dataset given, with no columns
- array and dataset
-
Treats as an insert based on a selection from the dataset given, with the columns given by the array.
Examples:
DB[:items].insert # INSERT INTO items DEFAULT VALUES DB[:items].insert({}) # INSERT INTO items DEFAULT VALUES DB[:items].insert([1,2,3]) # INSERT INTO items VALUES (1, 2, 3) DB[:items].insert([:a, :b], [1,2]) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(a: 1, b: 2) # INSERT INTO items (a, b) VALUES (1, 2) DB[:items].insert(DB[:old_items]) # INSERT INTO items SELECT * FROM old_items DB[:items].insert([:a, :b], DB[:old_items]) # INSERT INTO items (a, b) SELECT * FROM old_items
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# File lib/sequel/dataset/actions.rb 475 def last(*args, &block) 476 raise(Error, 'No order specified') unless @opts[:order] 477 reverse.first(*args, &block) 478 end
Reverses the order and then runs first with the given arguments and block. Note that this will not necessarily give you the last record in the dataset, unless you have an unambiguous order. If there is not currently an order for this dataset, raises an Error.
DB[:table].order(:id).last # SELECT * FROM table ORDER BY id DESC LIMIT 1 # => {:id=>10} DB[:table].order(Sequel.desc(:id)).last(2) # SELECT * FROM table ORDER BY id ASC LIMIT 2 # => [{:id=>1}, {:id=>2}]
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# File lib/sequel/dataset/actions.rb 494 def map(column=nil, &block) 495 if column 496 raise(Error, 'Must call Dataset#map with either an argument or a block, not both') if block 497 return naked.map(column) if row_proc 498 if column.is_a?(Array) 499 super(){|r| r.values_at(*column)} 500 else 501 super(){|r| r[column]} 502 end 503 else 504 super(&block) 505 end 506 end
Maps column values for each record in the dataset (if an argument is given) or performs the stock mapping functionality of Enumerable otherwise. Raises an Error if both an argument and block are given.
DB[:table].map(:id) # SELECT * FROM table # => [1, 2, 3, ...] DB[:table].map{|r| r[:id] * 2} # SELECT * FROM table # => [2, 4, 6, ...]
You can also provide an array of column names:
DB[:table].map([:id, :name]) # SELECT * FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
Source
# File lib/sequel/dataset/actions.rb 515 def max(arg=(no_arg = true), &block) 516 arg = Sequel.virtual_row(&block) if no_arg 517 _aggregate(:max, arg) 518 end
Returns the maximum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].max(:id) # SELECT max(id) FROM table LIMIT 1 # => 10 DB[:table].max{function(column)} # SELECT max(function(column)) FROM table LIMIT 1 # => 7
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# File lib/sequel/dataset/actions.rb 565 def merge 566 execute_ddl(merge_sql) 567 end
Execute a MERGE statement, which allows for INSERT, UPDATE, and DELETE behavior in a single query, based on whether rows from a source table match rows in the current table, based on the join conditions.
Unless the dataset uses static SQL, to use merge, you must first have called merge_using to specify the merge source and join conditions. You will then likely to call one or more of the following methods to specify MERGE behavior by adding WHEN [NOT] MATCHED clauses:
The WHEN [NOT] MATCHED clauses are added to the SQL in the order these methods were called on the dataset. If none of these methods are called, an error is raised.
Example:
DB[:m1] merge_using(:m2, i1: :i2). merge_insert(i1: :i2, a: Sequel[:b]+11). merge_delete{a > 30}. merge_update(i1: Sequel[:i1]+:i2+10, a: Sequel[:a]+:b+20). merge
SQL:
MERGE INTO m1 USING m2 ON (i1 = i2) WHEN NOT MATCHED THEN INSERT (i1, a) VALUES (i2, (b + 11)) WHEN MATCHED AND (a > 30) THEN DELETE WHEN MATCHED THEN UPDATE SET i1 = (i1 + i2 + 10), a = (a + b + 20)
On PostgreSQL, two additional merge methods are supported, for the PostgreSQL-specific DO NOTHING syntax.
-
merge_do_nothing_when_matched
-
merge_do_nothing_when_not_matched
This method is supported on Oracle, but Oracle’s MERGE support is non-standard, and has the following issues:
-
DELETE clause requires UPDATE clause
-
DELETE clause requires a condition
-
DELETE clause only affects rows updated by UPDATE clause
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# File lib/sequel/dataset/actions.rb 576 def min(arg=(no_arg = true), &block) 577 arg = Sequel.virtual_row(&block) if no_arg 578 _aggregate(:min, arg) 579 end
Returns the minimum value for the given column/expression. Uses a virtual row block if no argument is given.
DB[:table].min(:id) # SELECT min(id) FROM table LIMIT 1 # => 1 DB[:table].min{function(column)} # SELECT min(function(column)) FROM table LIMIT 1 # => 0
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# File lib/sequel/dataset/actions.rb 593 def multi_insert(hashes, opts=OPTS) 594 return if hashes.empty? 595 columns = hashes.first.keys 596 import(columns, hashes.map{|h| columns.map{|c| h[c]}}, opts) 597 end
This is a front end for import that allows you to submit an array of hashes instead of arrays of columns and values:
DB[:table].multi_insert([{x: 1}, {x: 2}]) # INSERT INTO table (x) VALUES (1) # INSERT INTO table (x) VALUES (2)
Be aware that all hashes should have the same keys if you use this calling method, otherwise some columns could be missed or set to null instead of to default values.
This respects the same options as import.
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# File lib/sequel/dataset/actions.rb 656 def paged_each(opts=OPTS) 657 unless @opts[:order] 658 raise Sequel::Error, "Dataset#paged_each requires the dataset be ordered" 659 end 660 unless defined?(yield) 661 return enum_for(:paged_each, opts) 662 end 663 664 total_limit = @opts[:limit] 665 offset = @opts[:offset] 666 if server = @opts[:server] 667 opts = Hash[opts] 668 opts[:server] = server 669 end 670 671 rows_per_fetch = opts[:rows_per_fetch] || 1000 672 strategy = if offset || total_limit 673 :offset 674 else 675 opts[:strategy] || :offset 676 end 677 678 db.transaction(opts) do 679 case strategy 680 when :filter 681 filter_values = opts[:filter_values] || proc{|row, exprs| exprs.map{|e| row[hash_key_symbol(e)]}} 682 base_ds = ds = limit(rows_per_fetch) 683 while ds 684 last_row = nil 685 ds.each do |row| 686 last_row = row 687 yield row 688 end 689 ds = (base_ds.where(ignore_values_preceding(last_row, &filter_values)) if last_row) 690 end 691 else 692 offset ||= 0 693 num_rows_yielded = rows_per_fetch 694 total_rows = 0 695 696 while num_rows_yielded == rows_per_fetch && (total_limit.nil? || total_rows < total_limit) 697 if total_limit && total_rows + rows_per_fetch > total_limit 698 rows_per_fetch = total_limit - total_rows 699 end 700 701 num_rows_yielded = 0 702 limit(rows_per_fetch, offset).each do |row| 703 num_rows_yielded += 1 704 total_rows += 1 if total_limit 705 yield row 706 end 707 708 offset += rows_per_fetch 709 end 710 end 711 end 712 713 self 714 end
Yields each row in the dataset, but internally uses multiple queries as needed to process the entire result set without keeping all rows in the dataset in memory, even if the underlying driver buffers all query results in memory.
Because this uses multiple queries internally, in order to remain consistent, it also uses a transaction internally. Additionally, to work correctly, the dataset must have unambiguous order. Using an ambiguous order can result in an infinite loop, as well as subtler bugs such as yielding duplicate rows or rows being skipped.
Sequel checks that the datasets using this method have an order, but it cannot ensure that the order is unambiguous.
Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, use a separate thread or shard inside paged_each.
Options:
- :rows_per_fetch
-
The number of rows to fetch per query. Defaults to 1000.
- :strategy
-
The strategy to use for paging of results. By default this is :offset, for using an approach with a limit and offset for every page. This can be set to :filter, which uses a limit and a filter that excludes rows from previous pages. In order for this strategy to work, you must be selecting the columns you are ordering by, and none of the columns can contain NULLs. Note that some
Sequeladapters have optimized implementations that will use cursors or streaming regardless of the :strategy option used. - :filter_values
-
If the strategy: :filter option is used, this option should be a proc that accepts the last retrieved row for the previous page and an array of ORDER BY expressions, and returns an array of values relating to those expressions for the last retrieved row. You will need to use this option if your ORDER BY expressions are not simple columns, if they contain qualified identifiers that would be ambiguous unqualified, if they contain any identifiers that are aliased in SELECT, and potentially other cases.
- :skip_transaction
-
Do not use a transaction. This can be useful if you want to prevent a lock on the database table, at the expense of consistency.
Examples:
DB[:table].order(:id).paged_each{|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table ORDER BY id LIMIT 1000 OFFSET 1000 # ... DB[:table].order(:id).paged_each(rows_per_fetch: 100){|row| } # SELECT * FROM table ORDER BY id LIMIT 100 # SELECT * FROM table ORDER BY id LIMIT 100 OFFSET 100 # ... DB[:table].order(:id).paged_each(strategy: :filter){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ... DB[:table].order(:id).paged_each(strategy: :filter, filter_values: lambda{|row, exprs| [row[:id]]}){|row| } # SELECT * FROM table ORDER BY id LIMIT 1000 # SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000 # ...
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# File lib/sequel/dataset/actions.rb 734 def select_hash(key_column, value_column, opts = OPTS) 735 _select_hash(:as_hash, key_column, value_column, opts) 736 end
Returns a hash with key_column values as keys and value_column values as values. Similar to as_hash, but only selects the columns given. Like as_hash, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash(:id, :name) # SELECT id, name FROM table # => {1=>'a', 2=>'b', ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash([:id, :foo], [:name, :bar]) # SELECT id, foo, name, bar FROM table # => {[1, 3]=>['a', 'c'], [2, 4]=>['b', 'd'], ...}
When using this method, you must be sure that each expression has an alias that Sequel can determine.
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# File lib/sequel/dataset/actions.rb 755 def select_hash_groups(key_column, value_column, opts = OPTS) 756 _select_hash(:to_hash_groups, key_column, value_column, opts) 757 end
Returns a hash with key_column values as keys and an array of value_column values. Similar to to_hash_groups, but only selects the columns given. Like to_hash_groups, it accepts an optional :hash parameter, into which entries will be merged.
DB[:table].select_hash_groups(:name, :id) # SELECT id, name FROM table # => {'a'=>[1, 4, ...], 'b'=>[2, ...], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].select_hash_groups([:first, :middle], [:last, :id]) # SELECT first, middle, last, id FROM table # => {['a', 'b']=>[['c', 1], ['d', 2], ...], ...}
When using this method, you must be sure that each expression has an alias that Sequel can determine.
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# File lib/sequel/dataset/actions.rb 775 def select_map(column=nil, &block) 776 _select_map(column, false, &block) 777 end
Selects the column given (either as an argument or as a block), and returns an array of all values of that column in the dataset.
DB[:table].select_map(:id) # SELECT id FROM table # => [3, 5, 8, 1, ...] DB[:table].select_map{id * 2} # SELECT (id * 2) FROM table # => [6, 10, 16, 2, ...]
You can also provide an array of column names:
DB[:table].select_map([:id, :name]) # SELECT id, name FROM table # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel can determine.
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# File lib/sequel/dataset/actions.rb 794 def select_order_map(column=nil, &block) 795 _select_map(column, true, &block) 796 end
The same as select_map, but in addition orders the array by the column.
DB[:table].select_order_map(:id) # SELECT id FROM table ORDER BY id # => [1, 2, 3, 4, ...] DB[:table].select_order_map{id * 2} # SELECT (id * 2) FROM table ORDER BY (id * 2) # => [2, 4, 6, 8, ...]
You can also provide an array of column names:
DB[:table].select_order_map([:id, :name]) # SELECT id, name FROM table ORDER BY id, name # => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel can determine.
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# File lib/sequel/dataset/actions.rb 815 def select_set(column=nil, &block) 816 ds = ungraphed.naked 817 columns = Array(column) 818 virtual_row_columns(columns, block) 819 if column.is_a?(Array) || (columns.length > 1) 820 ds.select(*columns)._select_set_multiple(hash_key_symbols(columns)) 821 else 822 ds.select(auto_alias_expression(columns.first))._select_set_single 823 end 824 end
Selects the column given (either as an argument or as a block), and returns a set of all values of that column in the dataset.
DB[:table].select_set(:id) # SELECT id FROM table # => Set[3, 5, 8, 1, ...] DB[:table].select_set{id * 2} # SELECT (id * 2) FROM table # => Set[6, 10, 16, 2, ...]
You can also provide an array of column names, which returns a set with array elements (not set elements):
DB[:table].select_map([:id, :name]) # SELECT id, name FROM table # => Set[[1, 'A'], [2, 'B'], [3, 'C'], ...]
If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel can determine.
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# File lib/sequel/dataset/actions.rb 832 def single_record 833 _single_record_ds.single_record! 834 end
Limits the dataset to one record, and returns the first record in the dataset, or nil if the dataset has no records. Users should probably use first instead of this method. Example:
DB[:test].single_record # SELECT * FROM test LIMIT 1 # => {:column_name=>'value'}
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# File lib/sequel/dataset/actions.rb 844 def single_record! 845 with_sql_first(select_sql) 846 end
Returns the first record in dataset, without limiting the dataset. Returns nil if the dataset has no records. Users should probably use first instead of this method. This should only be used if you know the dataset is already limited to a single record. This method may be desirable to use for performance reasons, as it does not clone the receiver. Example:
DB[:test].single_record! # SELECT * FROM test # => {:column_name=>'value'}
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# File lib/sequel/dataset/actions.rb 854 def single_value 855 single_value_ds.each do |r| 856 r.each{|_, v| return v} 857 end 858 nil 859 end
Returns the first value of the first record in the dataset. Returns nil if dataset is empty. Users should generally use get instead of this method. Example:
DB[:test].single_value # SELECT * FROM test LIMIT 1 # => 'value'
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# File lib/sequel/dataset/actions.rb 869 def single_value! 870 with_sql_single_value(select_sql) 871 end
Returns the first value of the first record in the dataset, without limiting the dataset. Returns nil if the dataset is empty. Users should generally use get instead of this method. Should not be used on graphed datasets or datasets that have row_procs that don’t return hashes. This method may be desirable to use for performance reasons, as it does not clone the receiver.
DB[:test].single_value! # SELECT * FROM test # => 'value'
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# File lib/sequel/dataset/actions.rb 880 def sum(arg=(no_arg = true), &block) 881 arg = Sequel.virtual_row(&block) if no_arg 882 _aggregate(:sum, arg) 883 end
Returns the sum for the given column/expression. Uses a virtual row block if no column is given.
DB[:table].sum(:id) # SELECT sum(id) FROM table LIMIT 1 # => 55 DB[:table].sum{function(column)} # SELECT sum(function(column)) FROM table LIMIT 1 # => 10
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# File lib/sequel/dataset/actions.rb 937 def to_hash(*a) 938 as_hash(*a) 939 end
Alias of as_hash for backwards compatibility.
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# File lib/sequel/dataset/actions.rb 965 def to_hash_groups(key_column, value_column = nil, opts = OPTS) 966 h = opts[:hash] || {} 967 meth = opts[:all] ? :all : :each 968 if value_column 969 return naked.to_hash_groups(key_column, value_column, opts) if row_proc 970 if value_column.is_a?(Array) 971 if key_column.is_a?(Array) 972 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r.values_at(*value_column)} 973 else 974 public_send(meth){|r| (h[r[key_column]] ||= []) << r.values_at(*value_column)} 975 end 976 else 977 if key_column.is_a?(Array) 978 public_send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r[value_column]} 979 else 980 public_send(meth){|r| (h[r[key_column]] ||= []) << r[value_column]} 981 end 982 end 983 elsif key_column.is_a?(Array) 984 public_send(meth){|r| (h[key_column.map{|k| r[k]}] ||= []) << r} 985 else 986 public_send(meth){|r| (h[r[key_column]] ||= []) << r} 987 end 988 h 989 end
Returns a hash with one column used as key and the values being an array of column values. If the value_column is not given or nil, uses the entire hash as the value.
DB[:table].to_hash_groups(:name, :id) # SELECT * FROM table # {'Jim'=>[1, 4, 16, ...], 'Bob'=>[2], ...} DB[:table].to_hash_groups(:name) # SELECT * FROM table # {'Jim'=>[{:id=>1, :name=>'Jim'}, {:id=>4, :name=>'Jim'}, ...], 'Bob'=>[{:id=>2, :name=>'Bob'}], ...}
You can also provide an array of column names for either the key_column, the value column, or both:
DB[:table].to_hash_groups([:first, :middle], [:last, :id]) # SELECT * FROM table # {['Jim', 'Bob']=>[['Smith', 1], ['Jackson', 4], ...], ...} DB[:table].to_hash_groups([:first, :middle]) # SELECT * FROM table # {['Jim', 'Bob']=>[{:id=>1, :first=>'Jim', :middle=>'Bob', :last=>'Smith'}, ...], ...}
Options:
- :all
-
Use all instead of each to retrieve the objects
- :hash
-
The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.
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# File lib/sequel/dataset/actions.rb 995 def truncate 996 execute_ddl(truncate_sql) 997 end
Truncates the dataset. Returns nil.
DB[:table].truncate # TRUNCATE table # => nil
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# File lib/sequel/dataset/actions.rb 1021 def update(values=OPTS, &block) 1022 sql = update_sql(values) 1023 if uses_returning?(:update) 1024 returning_fetch_rows(sql, &block) 1025 else 1026 execute_dui(sql) 1027 end 1028 end
Updates values for the dataset. The returned value is the number of rows updated. values should be a hash where the keys are columns to set and values are the values to which to set the columns.
DB[:table].update(x: nil) # UPDATE table SET x = NULL # => 10 DB[:table].update(x: Sequel[:x]+1, y: 0) # UPDATE table SET x = (x + 1), y = 0 # => 10
Some databases support using multiple tables in an UPDATE query. This requires multiple FROM tables (JOINs can also be used). As multiple FROM tables use an implicit CROSS JOIN, you should make sure your WHERE condition uses the appropriate filters for the FROM tables:
DB.from(:a, :b).join(:c, :d=>Sequel[:b][:e]).where{{a[:f]=>b[:g], a[:id]=>10}}. update(:f=>Sequel[:c][:h]) # UPDATE a # SET f = c.h # FROM b # INNER JOIN c ON (c.d = b.e) # WHERE ((a.f = b.g) AND (a.id = 10))
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# File lib/sequel/dataset/actions.rb 1036 def where_all(cond, &block) 1037 if loader = _where_loader([cond], nil) 1038 loader.all(filter_expr(cond), &block) 1039 else 1040 where(cond).all(&block) 1041 end 1042 end
Return an array of all rows matching the given filter condition, also yielding each row to the given block. Basically the same as where(cond).all(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_all(id: [1,2,3]) # SELECT * FROM table WHERE (id IN (1, 2, 3))
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# File lib/sequel/dataset/actions.rb 1050 def where_each(cond, &block) 1051 if loader = _where_loader([cond], nil) 1052 loader.each(filter_expr(cond), &block) 1053 else 1054 where(cond).each(&block) 1055 end 1056 end
Iterate over all rows matching the given filter condition, yielding each row to the given block. Basically the same as where(cond).each(&block), except it can be optimized to not create an intermediate dataset.
DB[:table].where_each(id: [1,2,3]){|row| p row} # SELECT * FROM table WHERE (id IN (1, 2, 3))
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# File lib/sequel/dataset/actions.rb 1065 def where_single_value(cond) 1066 if loader = cached_where_placeholder_literalizer([cond], nil, :_where_single_value_loader) do |pl| 1067 single_value_ds.where(pl.arg) 1068 end 1069 1070 loader.get(filter_expr(cond)) 1071 else 1072 where(cond).single_value 1073 end 1074 end
Filter the datasets using the given filter condition, then return a single value. This assumes that the dataset has already been setup to limit the selection to a single column. Basically the same as where(cond).single_value, except it can be optimized to not create an intermediate dataset.
DB[:table].select(:name).where_single_value(id: 1) # SELECT name FROM table WHERE (id = 1) LIMIT 1
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# File lib/sequel/dataset/actions.rb 1078 def with_sql_all(sql, &block) 1079 _all(block){|a| with_sql_each(sql){|r| a << r}} 1080 end
Run the given SQL and return an array of all rows. If a block is given, each row is yielded to the block after all rows are loaded. See with_sql_each.
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# File lib/sequel/dataset/actions.rb 1085 def with_sql_delete(sql) 1086 execute_dui(sql) 1087 end
Execute the given SQL and return the number of rows deleted. This exists solely as an optimization, replacing with_sql(sql).delete. It’s significantly faster as it does not require cloning the current dataset.
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# File lib/sequel/dataset/actions.rb 1091 def with_sql_each(sql) 1092 if rp = row_proc 1093 _with_sql_dataset.fetch_rows(sql){|r| yield rp.call(r)} 1094 else 1095 _with_sql_dataset.fetch_rows(sql){|r| yield r} 1096 end 1097 self 1098 end
Run the given SQL and yield each returned row to the block.
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# File lib/sequel/dataset/actions.rb 1102 def with_sql_first(sql) 1103 with_sql_each(sql){|r| return r} 1104 nil 1105 end
Run the given SQL and return the first row, or nil if no rows were returned. See with_sql_each.
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# File lib/sequel/dataset/actions.rb 1118 def with_sql_insert(sql) 1119 execute_insert(sql) 1120 end
Execute the given SQL and (on most databases) return the primary key of the inserted row.
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# File lib/sequel/dataset/actions.rb 1110 def with_sql_single_value(sql) 1111 if r = with_sql_first(sql) 1112 r.each{|_, v| return v} 1113 end 1114 end
Run the given SQL and return the first value in the first row, or nil if no rows were returned. For this to make sense, the SQL given should select only a single value. See with_sql_each.
Protected Instance Methods
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# File lib/sequel/dataset/actions.rb 1128 def _import(columns, values, opts) 1129 trans_opts = Hash[opts] 1130 trans_opts[:server] = @opts[:server] 1131 if opts[:return] == :primary_key 1132 _import_transaction(values, trans_opts){values.map{|v| insert(columns, v)}} 1133 else 1134 stmts = multi_insert_sql(columns, values) 1135 _import_transaction(stmts, trans_opts){stmts.each{|st| execute_dui(st)}} 1136 end 1137 end
Internals of import. If primary key values are requested, use separate insert commands for each row. Otherwise, call multi_insert_sql and execute each statement it gives separately. A transaction is only used if there are multiple statements to execute.
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# File lib/sequel/dataset/actions.rb 1140 def _select_map_multiple(ret_cols) 1141 map{|r| r.values_at(*ret_cols)} 1142 end
Return an array of arrays of values given by the symbols in ret_cols.
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# File lib/sequel/dataset/actions.rb 1145 def _select_map_single 1146 k = nil 1147 map{|r| r[k||=r.keys.first]} 1148 end
Returns an array of the first value in each row.
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# File lib/sequel/dataset/actions.rb 1151 def _select_set_multiple(ret_cols) 1152 to_set{|r| r.values_at(*ret_cols)} 1153 end
Return a set of arrays of values given by the symbols in ret_cols.
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# File lib/sequel/dataset/actions.rb 1156 def _select_set_single 1157 k = nil 1158 to_set{|r| r[k||=r.keys.first]} 1159 end
Returns a set of the first value in each row.
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# File lib/sequel/dataset/actions.rb 1162 def single_value_ds 1163 clone(:limit=>1).ungraphed.naked 1164 end
A dataset for returning single values from the current dataset.
Private Instance Methods
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# File lib/sequel/dataset/actions.rb 1178 def _aggregate(function, arg) 1179 if loader = cached_placeholder_literalizer(:"_#{function}_loader") do |pl| 1180 aggregate_dataset.limit(1).select(SQL::Function.new(function, pl.arg).as(function)) 1181 end 1182 loader.get(arg) 1183 else 1184 aggregate_dataset.get(SQL::Function.new(function, arg).as(function)) 1185 end 1186 end
Cached placeholder literalizer for methods that return values using aggregate functions.
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# File lib/sequel/dataset/actions.rb 1169 def _all(block) 1170 a = [] 1171 yield a 1172 post_load(a) 1173 a.each(&block) if block 1174 a 1175 end
Internals of all and with_sql_all
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# File lib/sequel/dataset/actions.rb 1286 def _hash_key_symbol(s, recursing=false) 1287 case s 1288 when Symbol 1289 _, c, a = split_symbol(s) 1290 (a || c).to_sym 1291 when SQL::Identifier, SQL::Wrapper 1292 _hash_key_symbol(s.value, true) 1293 when SQL::QualifiedIdentifier 1294 _hash_key_symbol(s.column, true) 1295 when SQL::AliasedExpression 1296 _hash_key_symbol(s.alias, true) 1297 when String 1298 s.to_sym if recursing 1299 end 1300 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Return nil if no hash key can be determined
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# File lib/sequel/dataset/actions.rb 1191 def _import_transaction(values, trans_opts, &block) 1192 # OK to mutate trans_opts as it is generated by _import 1193 trans_opts[:skip_transaction] = true if values.length <= 1 1194 @db.transaction(trans_opts, &block) 1195 end
Use a transaction when yielding to the block if multiple values/statements are provided. When only a single value or statement is provided, then yield without using a transaction.
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# File lib/sequel/dataset/actions.rb 1198 def _select_hash(meth, key_column, value_column, opts=OPTS) 1199 select(*(key_column.is_a?(Array) ? key_column : [key_column]) + (value_column.is_a?(Array) ? value_column : [value_column])). 1200 public_send(meth, hash_key_symbols(key_column), hash_key_symbols(value_column), opts) 1201 end
Internals of select_hash and select_hash_groups
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# File lib/sequel/dataset/actions.rb 1204 def _select_map(column, order, &block) 1205 ds = ungraphed.naked 1206 columns = Array(column) 1207 virtual_row_columns(columns, block) 1208 select_cols = order ? columns.map{|c| c.is_a?(SQL::OrderedExpression) ? c.expression : c} : columns 1209 ds = ds.order(*columns.map{|c| unaliased_identifier(c)}) if order 1210 if column.is_a?(Array) || (columns.length > 1) 1211 ds.select(*select_cols)._select_map_multiple(hash_key_symbols(select_cols)) 1212 else 1213 ds.select(auto_alias_expression(select_cols.first))._select_map_single 1214 end 1215 end
Internals of select_map and select_order_map
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# File lib/sequel/dataset/actions.rb 1218 def _single_record_ds 1219 cached_dataset(:_single_record_ds){clone(:limit=>1)} 1220 end
A cached dataset for a single record for this dataset.
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# File lib/sequel/dataset/actions.rb 1223 def _where_loader(where_args, where_block) 1224 cached_where_placeholder_literalizer(where_args, where_block, :_where_loader) do |pl| 1225 where(pl.arg) 1226 end 1227 end
Loader used for where_all and where_each.
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# File lib/sequel/dataset/actions.rb 1402 def _with_sql_dataset 1403 if @opts[:_with_sql_ds] 1404 self 1405 else 1406 cached_dataset(:_with_sql_ds) do 1407 clone(:_with_sql_ds=>true) 1408 end 1409 end 1410 end
Cached dataset to use for with_sql_#{all,each,first,single_value}. This is used so that the columns returned by the given SQL do not affect the receiver of the with_sql_* method.
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# File lib/sequel/dataset/actions.rb 1230 def auto_alias_expression(v) 1231 case v 1232 when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression 1233 v 1234 else 1235 SQL::AliasedExpression.new(v, :v) 1236 end 1237 end
Automatically alias the given expression if it does not have an identifiable alias.
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# File lib/sequel/dataset/actions.rb 1241 def default_import_slice 1242 nil 1243 end
The default number of rows that can be inserted in a single INSERT statement via import. The default is for no limit.
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# File lib/sequel/dataset/actions.rb 1246 def default_server_opts(opts) 1247 if @db.sharded? && !opts.has_key?(:server) 1248 opts = Hash[opts] 1249 opts[:server] = @opts[:server] || :default 1250 end 1251 opts 1252 end
Set the server to use to :default unless it is already set in the passed opts
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# File lib/sequel/dataset/actions.rb 1256 def execute(sql, opts=OPTS, &block) 1257 db = @db 1258 if db.sharded? && !opts.has_key?(:server) 1259 opts = Hash[opts] 1260 opts[:server] = @opts[:server] || (@opts[:lock] ? :default : :read_only) 1261 opts 1262 end 1263 db.execute(sql, opts, &block) 1264 end
Execute the given select SQL on the database using execute. Use the :read_only server unless a specific server is set.
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# File lib/sequel/dataset/actions.rb 1267 def execute_ddl(sql, opts=OPTS, &block) 1268 @db.execute_ddl(sql, default_server_opts(opts), &block) 1269 nil 1270 end
Execute the given SQL on the database using execute_ddl.
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# File lib/sequel/dataset/actions.rb 1273 def execute_dui(sql, opts=OPTS, &block) 1274 @db.execute_dui(sql, default_server_opts(opts), &block) 1275 end
Execute the given SQL on the database using execute_dui.
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# File lib/sequel/dataset/actions.rb 1278 def execute_insert(sql, opts=OPTS, &block) 1279 @db.execute_insert(sql, default_server_opts(opts), &block) 1280 end
Execute the given SQL on the database using execute_insert.
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# File lib/sequel/dataset/actions.rb 1306 def hash_key_symbol(s) 1307 if v = _hash_key_symbol(s) 1308 v 1309 else 1310 raise(Error, "#{s.inspect} is not supported, should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression") 1311 end 1312 end
Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Raise Error if the hash key symbol cannot be returned.
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# File lib/sequel/dataset/actions.rb 1317 def hash_key_symbols(s) 1318 s.is_a?(Array) ? s.map{|c| hash_key_symbol(c)} : hash_key_symbol(s) 1319 end
If s is an array, return an array with the given hash key symbols. Otherwise, return a hash key symbol for the given expression If a hash key symbol cannot be determined, raise an error.
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# File lib/sequel/dataset/actions.rb 1324 def ignore_values_preceding(row) 1325 order_exprs = @opts[:order].map do |v| 1326 if v.is_a?(SQL::OrderedExpression) 1327 descending = v.descending 1328 v = v.expression 1329 else 1330 descending = false 1331 end 1332 [v, descending] 1333 end 1334 1335 row_values = yield(row, order_exprs.map(&:first)) 1336 1337 last_expr = [] 1338 cond = order_exprs.zip(row_values).map do |(v, descending), value| 1339 expr = last_expr + [SQL::BooleanExpression.new(descending ? :< : :>, v, value)] 1340 last_expr += [SQL::BooleanExpression.new(:'=', v, value)] 1341 Sequel.&(*expr) 1342 end 1343 Sequel.|(*cond) 1344 end
Returns an expression that will ignore values preceding the given row, using the receiver’s current order. This yields the row and the array of order expressions to the block, which should return an array of values to use.
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# File lib/sequel/dataset/actions.rb 1347 def output_identifier(v) 1348 v = 'untitled' if v == '' 1349 v.to_s.downcase.to_sym 1350 end
Downcase identifiers by default when outputing them from the database.
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# File lib/sequel/dataset/actions.rb 1356 def post_load(all_records) 1357 end
This is run inside .all, after all of the records have been loaded via .each, but before any block passed to all is called. It is called with a single argument, an array of all returned records. Does nothing by default, added to make the model eager loading code simpler.
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# File lib/sequel/dataset/actions.rb 1362 def returning_fetch_rows(sql, &block) 1363 if block 1364 default_server.fetch_rows(sql, &block) 1365 nil 1366 else 1367 rows = [] 1368 default_server.fetch_rows(sql){|r| rows << r} 1369 rows 1370 end 1371 end
Called by insert/update/delete when returning is used. Yields each row as a plain hash to the block if one is given, or returns an array of plain hashes for all rows if a block is not given
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# File lib/sequel/dataset/actions.rb 1376 def unaliased_identifier(c) 1377 case c 1378 when Symbol 1379 table, column, aliaz = split_symbol(c) 1380 if aliaz 1381 table ? SQL::QualifiedIdentifier.new(table, column) : Sequel.identifier(column) 1382 else 1383 c 1384 end 1385 when SQL::AliasedExpression 1386 c.expression 1387 when SQL::OrderedExpression 1388 case expr = c.expression 1389 when Symbol, SQL::AliasedExpression 1390 SQL::OrderedExpression.new(unaliased_identifier(expr), c.descending, :nulls=>c.nulls) 1391 else 1392 c 1393 end 1394 else 1395 c 1396 end 1397 end
Return the unaliased part of the identifier. Handles both implicit aliases in symbols, as well as SQL::AliasedExpression objects. Other objects are returned as is.
3 - User Methods relating to SQL Creation
↑ topPublic Instance Methods
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# File lib/sequel/dataset/sql.rb 14 def exists 15 SQL::PlaceholderLiteralString.new(EXISTS, [self], true) 16 end
Returns an EXISTS clause for the dataset as an SQL::PlaceholderLiteralString.
DB.select(1).where(DB[:items].exists) # SELECT 1 WHERE (EXISTS (SELECT * FROM items))
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# File lib/sequel/dataset/sql.rb 22 def insert_sql(*values) 23 return static_sql(@opts[:sql]) if @opts[:sql] 24 25 check_insert_allowed! 26 27 columns, values = _parse_insert_sql_args(values) 28 if values.is_a?(Array) && values.empty? && !insert_supports_empty_values? 29 columns, values = insert_empty_columns_values 30 elsif values.is_a?(Dataset) && hoist_cte?(values) && supports_cte?(:insert) 31 ds, values = hoist_cte(values) 32 return ds.clone(:columns=>columns, :values=>values).send(:_insert_sql) 33 end 34 clone(:columns=>columns, :values=>values).send(:_insert_sql) 35 end
Returns an INSERT SQL query string. See insert.
DB[:items].insert_sql(a: 1) # => "INSERT INTO items (a) VALUES (1)"
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# File lib/sequel/dataset/sql.rb 40 def literal_append(sql, v) 41 case v 42 when Symbol 43 if skip_symbol_cache? 44 literal_symbol_append(sql, v) 45 else 46 unless l = db.literal_symbol(v) 47 l = String.new 48 literal_symbol_append(l, v) 49 db.literal_symbol_set(v, l) 50 end 51 sql << l 52 end 53 when String 54 case v 55 when LiteralString 56 literal_literal_string_append(sql, v) 57 when SQL::Blob 58 literal_blob_append(sql, v) 59 else 60 literal_string_append(sql, v) 61 end 62 when Integer 63 sql << literal_integer(v) 64 when Hash 65 literal_hash_append(sql, v) 66 when SQL::Expression 67 literal_expression_append(sql, v) 68 when Float 69 sql << literal_float(v) 70 when BigDecimal 71 sql << literal_big_decimal(v) 72 when NilClass 73 sql << literal_nil 74 when TrueClass 75 sql << literal_true 76 when FalseClass 77 sql << literal_false 78 when Array 79 literal_array_append(sql, v) 80 when Time 81 v.is_a?(SQLTime) ? literal_sqltime_append(sql, v) : literal_time_append(sql, v) 82 when DateTime 83 literal_datetime_append(sql, v) 84 when Date 85 literal_date_append(sql, v) 86 when Dataset 87 literal_dataset_append(sql, v) 88 when Set 89 literal_set_append(sql, v) 90 else 91 literal_other_append(sql, v) 92 end 93 end
Append a literal representation of a value to the given SQL string.
If an unsupported object is given, an Error is raised.
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# File lib/sequel/dataset/sql.rb 125 def literal_date_or_time(dt, raw=false) 126 value = case dt 127 when SQLTime 128 literal_sqltime(dt) 129 when Time 130 literal_time(dt) 131 when DateTime 132 literal_datetime(dt) 133 when Date 134 literal_date(dt) 135 else 136 raise TypeError, "unsupported type: #{dt.inspect}" 137 end 138 139 if raw 140 value.sub!(/\A'/, '') 141 value.sub!(/'\z/, '') 142 end 143 144 value 145 end
Literalize a date or time value, as a SQL string value with no typecasting. If raw is true, remove the surrounding single quotes. This is designed for usage by bound argument code that can work even if the auto_cast_date_and_time extension is used (either manually or implicitly in the related adapter).
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# File lib/sequel/dataset/sql.rb 96 def merge_sql 97 raise Error, "This database doesn't support MERGE" unless supports_merge? 98 if sql = opts[:sql] 99 return static_sql(sql) 100 end 101 if sql = cache_get(:_merge_sql) 102 return sql 103 end 104 source, join_condition = @opts[:merge_using] 105 raise Error, "No USING clause for MERGE" unless source 106 sql = @opts[:append_sql] || sql_string_origin 107 108 select_with_sql(sql) 109 sql << "MERGE INTO " 110 source_list_append(sql, @opts[:from]) 111 sql << " USING " 112 identifier_append(sql, source) 113 sql << " ON " 114 literal_append(sql, join_condition) 115 _merge_when_sql(sql) 116 cache_set(:_merge_sql, sql) if cache_sql? 117 sql 118 end
The SQL to use for the MERGE statement.
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# File lib/sequel/dataset/sql.rb 150 def multi_insert_sql(columns, values) 151 case multi_insert_sql_strategy 152 when :values 153 sql = LiteralString.new('VALUES ') 154 expression_list_append(sql, values.map{|r| Array(r)}) 155 [insert_sql(columns, sql)] 156 when :union 157 c = false 158 sql = LiteralString.new 159 u = ' UNION ALL SELECT ' 160 f = empty_from_sql 161 values.each do |v| 162 if c 163 sql << u 164 else 165 sql << 'SELECT ' 166 c = true 167 end 168 expression_list_append(sql, v) 169 sql << f if f 170 end 171 [insert_sql(columns, sql)] 172 else 173 values.map{|r| insert_sql(columns, r)} 174 end 175 end
Returns an array of insert statements for inserting multiple records. This method is used by multi_insert to format insert statements and expects a keys array and and an array of value arrays.
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# File lib/sequel/dataset/sql.rb 178 def sql 179 select_sql 180 end
Same as select_sql, not aliased directly to make subclassing simpler.
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# File lib/sequel/dataset/sql.rb 185 def truncate_sql 186 if opts[:sql] 187 static_sql(opts[:sql]) 188 else 189 check_truncation_allowed! 190 check_not_limited!(:truncate) 191 raise(InvalidOperation, "Can't truncate filtered datasets") if opts[:where] || opts[:having] 192 t = String.new 193 source_list_append(t, opts[:from]) 194 _truncate_sql(t) 195 end 196 end
Returns a TRUNCATE SQL query string. See truncate
DB[:items].truncate_sql # => 'TRUNCATE items'
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# File lib/sequel/dataset/sql.rb 205 def update_sql(values = OPTS) 206 return static_sql(opts[:sql]) if opts[:sql] 207 check_update_allowed! 208 check_not_limited!(:update) 209 210 case values 211 when LiteralString 212 # nothing 213 when String 214 raise Error, "plain string passed to Dataset#update is not supported, use Sequel.lit to use a literal string" 215 end 216 217 clone(:values=>values).send(:_update_sql) 218 end
Formats an UPDATE statement using the given values. See update.
DB[:items].update_sql(price: 100, category: 'software') # => "UPDATE items SET price = 100, category = 'software'
Raises an Error if the dataset is grouped or includes more than one table.
4 - Methods that describe what the dataset supports
↑ topPublic Instance Methods
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# File lib/sequel/dataset/features.rb 19 def provides_accurate_rows_matched? 20 true 21 end
Whether this dataset will provide accurate number of rows matched for delete and update statements, true by default. Accurate in this case is the number of rows matched by the dataset’s filter.
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# File lib/sequel/dataset/features.rb 12 def quote_identifiers? 13 @opts.fetch(:quote_identifiers, true) 14 end
Whether this dataset quotes identifiers.
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# File lib/sequel/dataset/features.rb 24 def recursive_cte_requires_column_aliases? 25 false 26 end
Whether you must use a column alias list for recursive CTEs, false by default.
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# File lib/sequel/dataset/features.rb 41 def requires_placeholder_type_specifiers? 42 false 43 end
Whether type specifiers are required for prepared statement/bound variable argument placeholders (i.e. :bv__integer), false by default.
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# File lib/sequel/dataset/features.rb 33 def requires_sql_standard_datetimes? 34 # SEQUEL6: Remove 35 false 36 end
Whether the dataset requires SQL standard datetimes. False by default, as most allow strings with ISO 8601 format. Only for backwards compatibility, no longer used internally, do not use in new code.
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# File lib/sequel/dataset/features.rb 48 def supports_cte?(type=:select) 49 false 50 end
Whether the dataset supports common table expressions, false by default. If given, type can be :select, :insert, :update, or :delete, in which case it determines whether WITH is supported for the respective statement type.
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# File lib/sequel/dataset/features.rb 55 def supports_cte_in_subqueries? 56 false 57 end
Whether the dataset supports common table expressions in subqueries, false by default. If false, applies the WITH clause to the main query, which can cause issues if multiple WITH clauses use the same name.
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# File lib/sequel/dataset/features.rb 60 def supports_deleting_joins? 61 supports_modifying_joins? 62 end
Whether deleting from joined datasets is supported, false by default.
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# File lib/sequel/dataset/features.rb 67 def supports_derived_column_lists? 68 true 69 end
Whether the database supports derived column lists (e.g. “table_expr AS table_alias(column_alias1, column_alias2, …)”), true by default.
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# File lib/sequel/dataset/features.rb 72 def supports_distinct_on? 73 false 74 end
Whether the dataset supports or can emulate the DISTINCT ON clause, false by default.
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# File lib/sequel/dataset/features.rb 77 def supports_group_cube? 78 false 79 end
Whether the dataset supports CUBE with GROUP BY, false by default.
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# File lib/sequel/dataset/features.rb 82 def supports_group_rollup? 83 false 84 end
Whether the dataset supports ROLLUP with GROUP BY, false by default.
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# File lib/sequel/dataset/features.rb 87 def supports_grouping_sets? 88 false 89 end
Whether the dataset supports GROUPING SETS with GROUP BY, false by default.
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# File lib/sequel/dataset/features.rb 93 def supports_insert_select? 94 supports_returning?(:insert) 95 end
Whether this dataset supports the insert_select method for returning all columns values directly from an insert query, false by default.
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# File lib/sequel/dataset/features.rb 98 def supports_intersect_except? 99 true 100 end
Whether the dataset supports the INTERSECT and EXCEPT compound operations, true by default.
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# File lib/sequel/dataset/features.rb 103 def supports_intersect_except_all? 104 true 105 end
Whether the dataset supports the INTERSECT ALL and EXCEPT ALL compound operations, true by default.
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# File lib/sequel/dataset/features.rb 108 def supports_is_true? 109 true 110 end
Whether the dataset supports the IS TRUE syntax, true by default.
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# File lib/sequel/dataset/features.rb 114 def supports_join_using? 115 true 116 end
Whether the dataset supports the JOIN table USING (column1, …) syntax, true by default. If false, support is emulated using JOIN table ON (table.column1 = other_table.column1).
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# File lib/sequel/dataset/features.rb 119 def supports_lateral_subqueries? 120 false 121 end
Whether the dataset supports LATERAL for subqueries in the FROM or JOIN clauses, false by default.
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# File lib/sequel/dataset/features.rb 134 def supports_merge? 135 false 136 end
Whether the MERGE statement is supported, false by default.
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# File lib/sequel/dataset/features.rb 139 def supports_modifying_joins? 140 false 141 end
Whether modifying joined datasets is supported, false by default.
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# File lib/sequel/dataset/features.rb 145 def supports_multiple_column_in? 146 true 147 end
Whether the IN/NOT IN operators support multiple columns when an array of values is given, true by default.
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# File lib/sequel/dataset/features.rb 129 def supports_nowait? 130 false 131 end
Whether the dataset supports skipping raising an error instead of waiting for locked rows when returning data, false by default.
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# File lib/sequel/dataset/features.rb 156 def supports_ordered_distinct_on? 157 supports_distinct_on? 158 end
Whether the dataset supports or can fully emulate the DISTINCT ON clause, including respecting the ORDER BY clause, false by default.
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# File lib/sequel/dataset/features.rb 161 def supports_placeholder_literalizer? 162 true 163 end
Whether placeholder literalizers are supported, true by default.
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# File lib/sequel/dataset/features.rb 166 def supports_regexp? 167 false 168 end
Whether the dataset supports pattern matching by regular expressions, false by default.
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# File lib/sequel/dataset/features.rb 171 def supports_replace? 172 false 173 end
Whether the dataset supports REPLACE syntax, false by default.
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# File lib/sequel/dataset/features.rb 177 def supports_returning?(type) 178 false 179 end
Whether the RETURNING clause is supported for the given type of query, false by default. type can be :insert, :update, or :delete.
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# File lib/sequel/dataset/features.rb 187 def supports_select_all_and_column? 188 true 189 end
Whether the database supports SELECT *, column FROM table, true by default.
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# File lib/sequel/dataset/features.rb 182 def supports_skip_locked? 183 false 184 end
Whether the dataset supports skipping locked rows when returning data, false by default.
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# File lib/sequel/dataset/features.rb 194 def supports_timestamp_timezones? 195 # SEQUEL6: Remove 196 false 197 end
Whether the dataset supports timezones in literal timestamps, false by default.
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# File lib/sequel/dataset/features.rb 201 def supports_timestamp_usecs? 202 true 203 end
Whether the dataset supports fractional seconds in literal timestamps, true by default.
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# File lib/sequel/dataset/features.rb 206 def supports_updating_joins? 207 supports_modifying_joins? 208 end
Whether updating joined datasets is supported, false by default.
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# File lib/sequel/dataset/features.rb 235 def supports_where_true? 236 true 237 end
Whether the dataset supports WHERE TRUE (or WHERE 1 for databases that that use 1 for true), true by default.
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# File lib/sequel/dataset/features.rb 212 def supports_window_clause? 213 false 214 end
Whether the dataset supports the WINDOW clause to define windows used by multiple window functions, false by default.
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# File lib/sequel/dataset/features.rb 224 def supports_window_function_frame_option?(option) 225 case option 226 when :rows, :range, :offset 227 true 228 else 229 false 230 end 231 end
Whether the dataset supports the given window function option. True by default. This should only be called if supports_window_functions? is true. Possible options are :rows, :range, :groups, :offset, :exclude.
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# File lib/sequel/dataset/features.rb 217 def supports_window_functions? 218 false 219 end
Whether the dataset supports window functions, false by default.
Private Instance Methods
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# File lib/sequel/dataset/features.rb 243 def insert_supports_empty_values? 244 true 245 end
Whether insert(nil) or insert({}) must be emulated by using at least one value.
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# File lib/sequel/dataset/features.rb 253 def requires_emulating_nulls_first? 254 false 255 end
Whether ORDER BY col NULLS FIRST/LAST must be emulated.
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# File lib/sequel/dataset/features.rb 248 def requires_like_escape? 249 true 250 end
Whether the dataset needs ESCAPE for LIKE for correct behavior.
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# File lib/sequel/dataset/features.rb 258 def supports_cte_in_compounds? 259 supports_cte_in_subqueries? 260 end
Whether common table expressions are supported in UNION/INTERSECT/EXCEPT clauses.
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# File lib/sequel/dataset/features.rb 264 def supports_filtered_aggregates? 265 false 266 end
Whether the dataset supports the FILTER clause for aggregate functions. If not, support is emulated using CASE.
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# File lib/sequel/dataset/features.rb 269 def supports_quoted_function_names? 270 false 271 end
Whether the database supports quoting function names.
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# File lib/sequel/dataset/features.rb 275 def uses_returning?(type) 276 opts[:returning] && !@opts[:sql] && supports_returning?(type) 277 end
Whether the RETURNING clause is used for the given dataset. type can be :insert, :update, or :delete.
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# File lib/sequel/dataset/features.rb 280 def uses_with_rollup? 281 false 282 end
Whether the dataset uses WITH ROLLUP/CUBE instead of ROLLUP()/CUBE().
6 - Miscellaneous methods
↑ topAttributes
The database related to this dataset. This is the Database instance that will execute all of this dataset’s queries.
The hash of options for this dataset, keys are symbols.
Public Class Methods
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# File lib/sequel/dataset/misc.rb 25 def initialize(db) 26 @db = db 27 @opts = OPTS 28 @cache = {} 29 freeze 30 end
Constructs a new Dataset instance with an associated database and options. Datasets are usually constructed by invoking the Database#[] method:
DB[:posts]
Sequel::Dataset is an abstract class that is not useful by itself. Each database adapter provides a subclass of Sequel::Dataset, and has the Database#dataset method return an instance of that subclass.
Public Instance Methods
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# File lib/sequel/dataset/misc.rb 34 def ==(o) 35 o.is_a?(self.class) && db == o.db && opts == o.opts 36 end
Define a hash value such that datasets with the same class, DB, and opts will be considered equal.
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# File lib/sequel/dataset/misc.rb 40 def current_datetime 41 Sequel.datetime_class.now 42 end
An object representing the current date or time, should be an instance of Sequel.datetime_class.
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# File lib/sequel/dataset/misc.rb 50 def dup 51 self 52 end
Return self, as datasets are always frozen.
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# File lib/sequel/dataset/misc.rb 59 def each_server 60 db.servers.each{|s| yield server(s)} 61 end
Yield a dataset for each server in the connection pool that is tied to that server. Intended for use in sharded environments where all servers need to be modified with the same data:
DB[:configs].where(key: 'setting').each_server{|ds| ds.update(value: 'new_value')}
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# File lib/sequel/dataset/misc.rb 68 def escape_like(string) 69 string.gsub(/[\\%_]/){|m| "\\#{m}"} 70 end
Returns the string with the LIKE metacharacters (% and _) escaped. Useful for when the LIKE term is a user-provided string where metacharacters should not be recognized. Example:
ds.escape_like("foo\\%_") # 'foo\\\%\_'
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# File lib/sequel/dataset/misc.rb 91 def first_source 92 first_source_alias 93 end
Alias of first_source_alias
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# File lib/sequel/dataset/misc.rb 103 def first_source_alias 104 source = @opts[:from] 105 if source.nil? || source.empty? 106 raise Error, 'No source specified for query' 107 end 108 case s = source.first 109 when SQL::AliasedExpression 110 s.alias 111 when Symbol 112 _, _, aliaz = split_symbol(s) 113 aliaz ? aliaz.to_sym : s 114 else 115 s 116 end 117 end
The first source (primary table) for this dataset. If the dataset doesn’t have a table, raises an Error. If the table is aliased, returns the aliased name.
DB[:table].first_source_alias # => :table DB[Sequel[:table].as(:t)].first_source_alias # => :t
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# File lib/sequel/dataset/misc.rb 128 def first_source_table 129 source = @opts[:from] 130 if source.nil? || source.empty? 131 raise Error, 'No source specified for query' 132 end 133 case s = source.first 134 when SQL::AliasedExpression 135 s.expression 136 when Symbol 137 sch, table, aliaz = split_symbol(s) 138 aliaz ? (sch ? SQL::QualifiedIdentifier.new(sch, table) : table.to_sym) : s 139 else 140 s 141 end 142 end
The first source (primary table) for this dataset. If the dataset doesn’t have a table, raises an error. If the table is aliased, returns the original table, not the alias
DB[:table].first_source_table # => :table DB[Sequel[:table].as(:t)].first_source_table # => :table
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# File lib/sequel/dataset/misc.rb 74 def freeze 75 @opts.freeze 76 super 77 end
Freeze the opts when freezing the dataset.
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# File lib/sequel/dataset/misc.rb 146 def hash 147 [self.class, db, opts].hash 148 end
Define a hash value such that datasets with the same class, DB, and opts, will have the same hash value.
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# File lib/sequel/dataset/misc.rb 152 def inspect 153 "#<#{visible_class_name}: #{sql.inspect}>" 154 end
Returns a string representation of the dataset including the class name and the corresponding SQL select statement.
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# File lib/sequel/dataset/misc.rb 157 def joined_dataset? 158 !!((opts[:from].is_a?(Array) && opts[:from].size > 1) || opts[:join]) 159 end
Whether this dataset is a joined dataset (multiple FROM tables or any JOINs).
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# File lib/sequel/dataset/misc.rb 162 def placeholder_literalizer_class 163 ::Sequel::Dataset::PlaceholderLiteralizer 164 end
The class to use for placeholder literalizers for the current dataset.
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# File lib/sequel/dataset/misc.rb 167 def placeholder_literalizer_loader(&block) 168 placeholder_literalizer_class.loader(self, &block) 169 end
A placeholder literalizer loader for the current dataset.
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# File lib/sequel/dataset/misc.rb 173 def row_number_column 174 :x_sequel_row_number_x 175 end
The alias to use for the row_number column, used when emulating OFFSET support and for eager limit strategies
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# File lib/sequel/dataset/misc.rb 186 def split_alias(c) 187 case c 188 when Symbol 189 c_table, column, aliaz = split_symbol(c) 190 [c_table ? SQL::QualifiedIdentifier.new(c_table, column.to_sym) : column.to_sym, aliaz] 191 when SQL::AliasedExpression 192 [c.expression, c.alias] 193 when SQL::JoinClause 194 [c.table, c.table_alias] 195 else 196 [c, nil] 197 end 198 end
Splits a possible implicit alias in c, handling both SQL::AliasedExpressions and Symbols. Returns an array of two elements, with the first being the main expression, and the second being the alias.
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# File lib/sequel/dataset/misc.rb 205 def unqualified_column_for(v) 206 unless v.is_a?(String) 207 _unqualified_column_for(v) 208 end 209 end
This returns an SQL::Identifier or SQL::AliasedExpression containing an SQL identifier that represents the unqualified column for the given value. The given value should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression containing one of those. In other cases, this returns nil.
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# File lib/sequel/dataset/misc.rb 233 def unused_table_alias(table_alias, used_aliases = []) 234 table_alias = alias_symbol(table_alias) 235 used_aliases += opts[:from].map{|t| alias_symbol(t)} if opts[:from] 236 used_aliases += opts[:join].map{|j| j.table_alias ? alias_alias_symbol(j.table_alias) : alias_symbol(j.table)} if opts[:join] 237 if used_aliases.include?(table_alias) 238 i = 0 239 while true 240 ta = :"#{table_alias}_#{i}" 241 return ta unless used_aliases.include?(ta) 242 i += 1 243 end 244 else 245 table_alias 246 end 247 end
Creates a unique table alias that hasn’t already been used in the dataset. table_alias can be any type of object accepted by alias_symbol. The symbol returned will be the implicit alias in the argument, possibly appended with “_N” if the implicit alias has already been used, where N is an integer starting at 0 and increasing until an unused one is found.
You can provide a second addition array argument containing symbols that should not be considered valid table aliases. The current aliases for the FROM and JOIN tables are automatically included in this array.
DB[:table].unused_table_alias(:t) # => :t DB[:table].unused_table_alias(:table) # => :table_0 DB[:table, :table_0].unused_table_alias(:table) # => :table_1 DB[:table, :table_0].unused_table_alias(:table, [:table_1, :table_2]) # => :table_3
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# File lib/sequel/dataset/misc.rb 250 def with_quote_identifiers(v) 251 clone(:quote_identifiers=>v, :skip_symbol_cache=>true) 252 end
Return a modified dataset with quote_identifiers set.
Protected Instance Methods
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# File lib/sequel/dataset/misc.rb 281 def _columns 282 cache_get(:_columns) 283 end
The cached columns for the current dataset.
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# File lib/sequel/dataset/misc.rb 263 def cache_get(k) 264 Sequel.synchronize{@cache[k]} 265 end
Retreive a value from the dataset’s cache in a thread safe manner.
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# File lib/sequel/dataset/misc.rb 268 def cache_set(k, v) 269 Sequel.synchronize{@cache[k] = v} 270 end
Set a value in the dataset’s cache in a thread safe manner.
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# File lib/sequel/dataset/misc.rb 276 def clear_columns_cache 277 @cache.delete(:_columns) 278 end
Clear the columns hash for the current dataset. This is not a thread safe operation, so it should only be used if the dataset could not be used by another thread (such as one that was just created via clone).
Private Instance Methods
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# File lib/sequel/dataset/misc.rb 355 def _unqualified_column_for(v) 356 case v 357 when Symbol 358 _, c, a = Sequel.split_symbol(v) 359 c = Sequel.identifier(c) 360 a ? c.as(a) : c 361 when String 362 Sequel.identifier(v) 363 when SQL::Identifier 364 v 365 when SQL::QualifiedIdentifier 366 _unqualified_column_for(v.column) 367 when SQL::AliasedExpression 368 if expr = unqualified_column_for(v.expression) 369 SQL::AliasedExpression.new(expr, v.alias) 370 end 371 end 372 end
Internal recursive version of unqualified_column_for, handling Strings inside of other objects.
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# File lib/sequel/dataset/misc.rb 289 def cached_dataset(key) 290 unless ds = cache_get(key) 291 ds = yield 292 cache_set(key, ds) 293 end 294 295 ds 296 end
Check the cache for the given key, returning the value. Otherwise, yield to get the dataset and cache the dataset under the given key.
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# File lib/sequel/dataset/misc.rb 303 def cached_placeholder_literalizer(key) 304 if loader = cache_get(key) 305 return loader unless loader.is_a?(Integer) 306 loader += 1 307 308 if loader >= 3 309 loader = placeholder_literalizer_loader{|pl, _| yield pl} 310 cache_set(key, loader) 311 else 312 cache_set(key, loader + 1) 313 loader = nil 314 end 315 elsif cache_sql? && supports_placeholder_literalizer? 316 cache_set(key, 1) 317 end 318 319 loader 320 end
Return a cached placeholder literalizer for the given key if there is one for this dataset. If there isn’t one, increment the counter for the number of calls for the key, and if the counter is at least three, then create a placeholder literalizer by yielding to the block, and cache it.
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# File lib/sequel/dataset/misc.rb 327 def cached_where_placeholder_literalizer(where_args, where_block, key, &block) 328 where_args = where_args[0] if where_args.length == 1 329 unless where_block 330 return if where_args == OPTS || where_args == EMPTY_ARRAY 331 end 332 333 cached_placeholder_literalizer(key, &block) 334 end
Return a cached placeholder literalizer for the key, unless where_block is nil and where_args is an empty array or hash. This is designed to guard against placeholder literalizer use when passing arguments to where in the uncached case and filter_expr if a cached placeholder literalizer is used.
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# File lib/sequel/dataset/misc.rb 337 def columns=(v) 338 cache_set(:_columns, v) 339 end
Set the columns for the current dataset.
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# File lib/sequel/dataset/misc.rb 342 def initialize_clone(c, _=nil) 343 @db = c.db 344 @opts = Hash[c.opts] 345 if cols = c.cache_get(:_columns) 346 @cache = {:_columns=>cols} 347 else 348 @cache = {} 349 end 350 end
Set the db, opts, and cache for the copy of the dataset.
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# File lib/sequel/dataset/misc.rb 375 def visible_class_name 376 c = self.class 377 c = c.superclass while c.name.nil? || c.name == '' 378 c.name 379 end
Return the class name for this dataset, but skip anonymous classes
9 - Internal Methods relating to SQL Creation
↑ topConstants
- BITWISE_METHOD_MAP
- COUNT_FROM_SELF_OPTS
- COUNT_OF_ALL_AS_COUNT
- DEFAULT
- EXISTS
- IS_LITERALS
- IS_OPERATORS
- LIKE_OPERATORS
- MERGE_NORMALIZE_TYPE_MAP
- MERGE_TYPE_SQL
-
Mapping of merge types to related
SQL - N_ARITY_OPERATORS
- QUALIFY_KEYS
- REGEXP_OPERATORS
- TWO_ARITY_OPERATORS
- WILDCARD
Public Class Methods
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# File lib/sequel/dataset/sql.rb 227 def self.clause_methods(type, clauses) 228 clauses.map{|clause| :"#{type}_#{clause}_sql"}.freeze 229 end
Given a type (e.g. select) and an array of clauses, return an array of methods to call to build the SQL string.
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# File lib/sequel/dataset/sql.rb 241 def self.def_sql_method(mod, type, clauses) 242 priv = type == :update || type == :insert 243 cacheable = type == :select || type == :delete 244 245 lines = [] 246 lines << 'private' if priv 247 lines << "def #{'_' if priv}#{type}_sql" 248 lines << 'if sql = opts[:sql]; return static_sql(sql) end' unless priv 249 lines << "if sql = cache_get(:_#{type}_sql); return sql end" if cacheable 250 lines << 'check_delete_allowed!' << 'check_not_limited!(:delete)' if type == :delete 251 lines << 'sql = @opts[:append_sql] || sql_string_origin' 252 253 if clauses.all?{|c| c.is_a?(Array)} 254 clauses.each do |i, cs| 255 lines << i 256 lines.concat(clause_methods(type, cs).map{|x| "#{x}(sql)"}) 257 end 258 lines << 'end' 259 else 260 lines.concat(clause_methods(type, clauses).map{|x| "#{x}(sql)"}) 261 end 262 263 lines << "cache_set(:_#{type}_sql, sql) if cache_sql?" if cacheable 264 lines << 'sql' 265 lines << 'end' 266 267 mod.class_eval lines.join("\n"), __FILE__, __LINE__ 268 end
Define a dataset literalization method for the given type in the given module, using the given clauses.
Arguments:
- mod
-
Module in which to define method
- type
-
Type of
SQLliteralization method to create, either :select, :insert, :update, or :delete - clauses
-
array of clauses that make up the
SQLquery for the type. This can either be a single array of symbols/strings, or it can be an array of pairs, with the first element in each pair being an if/elsif/else code fragment, and the second element in each pair being an array of symbol/strings for the appropriate branch.
Public Instance Methods
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# File lib/sequel/dataset/sql.rb 302 def aliased_expression_sql_append(sql, ae) 303 literal_append(sql, ae.expression) 304 as_sql_append(sql, ae.alias, ae.columns) 305 end
Append literalization of aliased expression to SQL string.
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# File lib/sequel/dataset/sql.rb 308 def array_sql_append(sql, a) 309 if a.empty? 310 sql << '(NULL)' 311 else 312 sql << '(' 313 expression_list_append(sql, a) 314 sql << ')' 315 end 316 end
Append literalization of array to SQL string.
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# File lib/sequel/dataset/sql.rb 319 def boolean_constant_sql_append(sql, constant) 320 if (constant == true || constant == false) && !supports_where_true? 321 sql << (constant == true ? '(1 = 1)' : '(1 = 0)') 322 else 323 literal_append(sql, constant) 324 end 325 end
Append literalization of boolean constant to SQL string.
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# File lib/sequel/dataset/sql.rb 328 def case_expression_sql_append(sql, ce) 329 sql << '(CASE' 330 if ce.expression? 331 sql << ' ' 332 literal_append(sql, ce.expression) 333 end 334 w = " WHEN " 335 t = " THEN " 336 ce.conditions.each do |c,r| 337 sql << w 338 literal_append(sql, c) 339 sql << t 340 literal_append(sql, r) 341 end 342 sql << " ELSE " 343 literal_append(sql, ce.default) 344 sql << " END)" 345 end
Append literalization of case expression to SQL string.
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# File lib/sequel/dataset/sql.rb 348 def cast_sql_append(sql, expr, type) 349 sql << 'CAST(' 350 literal_append(sql, expr) 351 sql << ' AS ' << db.cast_type_literal(type).to_s 352 sql << ')' 353 end
Append literalization of cast expression to SQL string.
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# File lib/sequel/dataset/sql.rb 356 def column_all_sql_append(sql, ca) 357 qualified_identifier_sql_append(sql, ca.table, WILDCARD) 358 end
Append literalization of column all selection to SQL string.
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# File lib/sequel/dataset/sql.rb 361 def complex_expression_sql_append(sql, op, args) 362 case op 363 when *IS_OPERATORS 364 r = args[1] 365 if r.nil? || supports_is_true? 366 raise(InvalidOperation, 'Invalid argument used for IS operator') unless val = IS_LITERALS[r] 367 sql << '(' 368 literal_append(sql, args[0]) 369 sql << ' ' << op.to_s << ' ' 370 sql << val << ')' 371 elsif op == :IS 372 complex_expression_sql_append(sql, :"=", args) 373 else 374 complex_expression_sql_append(sql, :OR, [SQL::BooleanExpression.new(:"!=", *args), SQL::BooleanExpression.new(:IS, args[0], nil)]) 375 end 376 when :IN, :"NOT IN" 377 cols = args[0] 378 vals = args[1] 379 col_array = true if cols.is_a?(Array) 380 if vals.is_a?(Array) || vals.is_a?(Set) 381 val_array = true 382 empty_val_array = vals.empty? 383 end 384 if empty_val_array 385 literal_append(sql, empty_array_value(op, cols)) 386 elsif col_array 387 if !supports_multiple_column_in? 388 if val_array 389 expr = SQL::BooleanExpression.new(:OR, *vals.to_a.map{|vs| SQL::BooleanExpression.from_value_pairs(cols.to_a.zip(vs).map{|c, v| [c, v]})}) 390 literal_append(sql, op == :IN ? expr : ~expr) 391 else 392 old_vals = vals 393 vals = vals.naked if vals.is_a?(Sequel::Dataset) 394 vals = vals.to_a 395 val_cols = old_vals.columns 396 complex_expression_sql_append(sql, op, [cols, vals.map!{|x| x.values_at(*val_cols)}]) 397 end 398 else 399 # If the columns and values are both arrays, use array_sql instead of 400 # literal so that if values is an array of two element arrays, it 401 # will be treated as a value list instead of a condition specifier. 402 sql << '(' 403 literal_append(sql, cols) 404 sql << ' ' << op.to_s << ' ' 405 if val_array 406 array_sql_append(sql, vals) 407 else 408 literal_append(sql, vals) 409 end 410 sql << ')' 411 end 412 else 413 sql << '(' 414 literal_append(sql, cols) 415 sql << ' ' << op.to_s << ' ' 416 literal_append(sql, vals) 417 sql << ')' 418 end 419 when :LIKE, :'NOT LIKE' 420 sql << '(' 421 literal_append(sql, args[0]) 422 sql << ' ' << op.to_s << ' ' 423 literal_append(sql, args[1]) 424 if requires_like_escape? 425 sql << " ESCAPE " 426 literal_append(sql, "\\") 427 end 428 sql << ')' 429 when :ILIKE, :'NOT ILIKE' 430 complex_expression_sql_append(sql, (op == :ILIKE ? :LIKE : :"NOT LIKE"), args.map{|v| Sequel.function(:UPPER, v)}) 431 when :** 432 function_sql_append(sql, Sequel.function(:power, *args)) 433 when *TWO_ARITY_OPERATORS 434 if REGEXP_OPERATORS.include?(op) && !supports_regexp? 435 raise InvalidOperation, "Pattern matching via regular expressions is not supported on #{db.database_type}" 436 end 437 sql << '(' 438 literal_append(sql, args[0]) 439 sql << ' ' << op.to_s << ' ' 440 literal_append(sql, args[1]) 441 sql << ')' 442 when *N_ARITY_OPERATORS 443 sql << '(' 444 c = false 445 op_str = " #{op} " 446 args.each do |a| 447 sql << op_str if c 448 literal_append(sql, a) 449 c ||= true 450 end 451 sql << ')' 452 when :NOT 453 sql << 'NOT ' 454 literal_append(sql, args[0]) 455 when :NOOP 456 literal_append(sql, args[0]) 457 when :'B~' 458 sql << '~' 459 literal_append(sql, args[0]) 460 when :extract 461 sql << 'extract(' << args[0].to_s << ' FROM ' 462 literal_append(sql, args[1]) 463 sql << ')' 464 else 465 raise(InvalidOperation, "invalid operator #{op}") 466 end 467 end
Append literalization of complex expression to SQL string.
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# File lib/sequel/dataset/sql.rb 470 def constant_sql_append(sql, constant) 471 sql << constant.to_s 472 end
Append literalization of constant to SQL string.
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# File lib/sequel/dataset/sql.rb 476 def delayed_evaluation_sql_append(sql, delay) 477 # Delayed evaluations are used specifically so the SQL 478 # can differ in subsequent calls, so we definitely don't 479 # want to cache the sql in this case. 480 disable_sql_caching! 481 482 if recorder = @opts[:placeholder_literalizer] 483 recorder.use(sql, lambda{delay.call(self)}, nil) 484 else 485 literal_append(sql, delay.call(self)) 486 end 487 end
Append literalization of delayed evaluation to SQL string, causing the delayed evaluation proc to be evaluated.
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# File lib/sequel/dataset/sql.rb 490 def function_sql_append(sql, f) 491 name = f.name 492 opts = f.opts 493 494 if opts[:emulate] 495 if emulate_function?(name) 496 emulate_function_sql_append(sql, f) 497 return 498 end 499 500 name = native_function_name(name) 501 end 502 503 sql << 'LATERAL ' if opts[:lateral] 504 505 case name 506 when SQL::Identifier 507 if supports_quoted_function_names? && opts[:quoted] 508 literal_append(sql, name) 509 else 510 sql << name.value.to_s 511 end 512 when SQL::QualifiedIdentifier 513 if supports_quoted_function_names? && opts[:quoted] != false 514 literal_append(sql, name) 515 else 516 sql << split_qualifiers(name).join('.') 517 end 518 else 519 if supports_quoted_function_names? && opts[:quoted] 520 quote_identifier_append(sql, name) 521 else 522 sql << name.to_s 523 end 524 end 525 526 sql << '(' 527 if filter = opts[:filter] 528 filter = filter_expr(filter, &opts[:filter_block]) 529 end 530 if opts[:*] 531 if filter && !supports_filtered_aggregates? 532 literal_append(sql, Sequel.case({filter=>1}, nil)) 533 filter = nil 534 else 535 sql << '*' 536 end 537 else 538 sql << "DISTINCT " if opts[:distinct] 539 if filter && !supports_filtered_aggregates? 540 expression_list_append(sql, f.args.map{|arg| Sequel.case({filter=>arg}, nil)}) 541 filter = nil 542 else 543 expression_list_append(sql, f.args) 544 end 545 if order = opts[:order] 546 sql << " ORDER BY " 547 expression_list_append(sql, order) 548 end 549 end 550 sql << ')' 551 552 if group = opts[:within_group] 553 sql << " WITHIN GROUP (ORDER BY " 554 expression_list_append(sql, group) 555 sql << ')' 556 end 557 558 if filter 559 sql << " FILTER (WHERE " 560 literal_append(sql, filter) 561 sql << ')' 562 end 563 564 if window = opts[:over] 565 sql << ' OVER ' 566 window_sql_append(sql, window.opts) 567 end 568 569 if opts[:with_ordinality] 570 sql << " WITH ORDINALITY" 571 end 572 end
Append literalization of function call to SQL string.
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# File lib/sequel/dataset/sql.rb 575 def join_clause_sql_append(sql, jc) 576 table = jc.table 577 table_alias = jc.table_alias 578 table_alias = nil if table == table_alias && !jc.column_aliases 579 sql << ' ' << join_type_sql(jc.join_type) << ' ' 580 identifier_append(sql, table) 581 as_sql_append(sql, table_alias, jc.column_aliases) if table_alias 582 end
Append literalization of JOIN clause without ON or USING to SQL string.
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# File lib/sequel/dataset/sql.rb 585 def join_on_clause_sql_append(sql, jc) 586 join_clause_sql_append(sql, jc) 587 sql << ' ON ' 588 literal_append(sql, filter_expr(jc.on)) 589 end
Append literalization of JOIN ON clause to SQL string.
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# File lib/sequel/dataset/sql.rb 592 def join_using_clause_sql_append(sql, jc) 593 join_clause_sql_append(sql, jc) 594 join_using_clause_using_sql_append(sql, jc.using) 595 end
Append literalization of JOIN USING clause to SQL string.
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# File lib/sequel/dataset/sql.rb 598 def negative_boolean_constant_sql_append(sql, constant) 599 sql << 'NOT ' 600 boolean_constant_sql_append(sql, constant) 601 end
Append literalization of negative boolean constant to SQL string.
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# File lib/sequel/dataset/sql.rb 604 def ordered_expression_sql_append(sql, oe) 605 if emulate = requires_emulating_nulls_first? 606 case oe.nulls 607 when :first 608 null_order = 0 609 when :last 610 null_order = 2 611 end 612 613 if null_order 614 literal_append(sql, Sequel.case({{oe.expression=>nil}=>null_order}, 1)) 615 sql << ", " 616 end 617 end 618 619 literal_append(sql, oe.expression) 620 sql << (oe.descending ? ' DESC' : ' ASC') 621 622 unless emulate 623 case oe.nulls 624 when :first 625 sql << " NULLS FIRST" 626 when :last 627 sql << " NULLS LAST" 628 end 629 end 630 end
Append literalization of ordered expression to SQL string.
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# File lib/sequel/dataset/sql.rb 633 def placeholder_literal_string_sql_append(sql, pls) 634 args = pls.args 635 str = pls.str 636 sql << '(' if pls.parens 637 if args.is_a?(Hash) 638 if args.empty? 639 sql << str 640 else 641 re = /:(#{Regexp.union(args.keys.map(&:to_s))})\b/ 642 until str.empty? 643 previous, q, str = str.partition(re) 644 sql << previous 645 literal_append(sql, args[$1.to_sym]) unless q.empty? 646 end 647 end 648 elsif str.is_a?(Array) 649 len = args.length 650 str.each_with_index do |s, i| 651 sql << s 652 literal_append(sql, args[i]) unless i == len 653 end 654 unless str.length == args.length || str.length == args.length + 1 655 raise Error, "Mismatched number of placeholders (#{str.length}) and placeholder arguments (#{args.length}) when using placeholder array" 656 end 657 else 658 i = -1 659 match_len = args.length - 1 660 while true 661 previous, q, str = str.partition('?') 662 sql << previous 663 literal_append(sql, args.at(i+=1)) unless q.empty? 664 if str.empty? 665 unless i == match_len 666 raise Error, "Mismatched number of placeholders (#{i+1}) and placeholder arguments (#{args.length}) when using placeholder string" 667 end 668 break 669 end 670 end 671 end 672 sql << ')' if pls.parens 673 end
Append literalization of placeholder literal string to SQL string.
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# File lib/sequel/dataset/sql.rb 678 def qualified_identifier_sql_append(sql, table, column=(c = table.column; table = table.table; c)) 679 identifier_append(sql, table) 680 sql << '.' 681 identifier_append(sql, column) 682 end
Append literalization of qualified identifier to SQL string. If 3 arguments are given, the 2nd should be the table/qualifier and the third should be column/qualified. If 2 arguments are given, the 2nd should be an SQL::QualifiedIdentifier.
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# File lib/sequel/dataset/sql.rb 688 def quote_identifier_append(sql, name) 689 name = name.value if name.is_a?(SQL::Identifier) 690 if name.is_a?(LiteralString) 691 sql << name 692 else 693 name = input_identifier(name) 694 if quote_identifiers? 695 quoted_identifier_append(sql, name) 696 else 697 sql << name 698 end 699 end 700 end
Append literalization of unqualified identifier to SQL string. Adds quoting to identifiers (columns and tables). If identifiers are not being quoted, returns name as a string. If identifiers are being quoted quote the name with quoted_identifier.
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# File lib/sequel/dataset/sql.rb 703 def quote_schema_table_append(sql, table) 704 qualifiers = split_qualifiers(table) 705 table = qualifiers.pop 706 707 qualifiers.each do |q| 708 quote_identifier_append(sql, q) 709 sql << '.' 710 end 711 712 quote_identifier_append(sql, table) 713 end
Append literalization of identifier or unqualified identifier to SQL string.
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# File lib/sequel/dataset/sql.rb 719 def quoted_identifier_append(sql, name) 720 sql << '"' << name.to_s.gsub('"', '""') << '"' 721 end
Append literalization of quoted identifier to SQL string. This method quotes the given name with the SQL standard double quote. should be overridden by subclasses to provide quoting not matching the SQL standard, such as backtick (used by MySQL and SQLite).
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# File lib/sequel/dataset/sql.rb 730 def schema_and_table(table_name, sch=nil) 731 sch = sch.to_s if sch 732 case table_name 733 when Symbol 734 s, t, _ = split_symbol(table_name) 735 [s||sch, t] 736 when SQL::QualifiedIdentifier 737 [table_name.table.to_s, table_name.column.to_s] 738 when SQL::Identifier 739 [sch, table_name.value.to_s] 740 when String 741 [sch, table_name] 742 else 743 raise Error, 'table_name should be a Symbol, SQL::QualifiedIdentifier, SQL::Identifier, or String' 744 end 745 end
Split the schema information from the table, returning two strings, one for the schema and one for the table. The returned schema may be nil, but the table will always have a string value.
Note that this function does not handle tables with more than one level of qualification (e.g. database.schema.table on Microsoft SQL Server).
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# File lib/sequel/dataset/sql.rb 753 def split_qualifiers(table_name, *args) 754 case table_name 755 when SQL::QualifiedIdentifier 756 split_qualifiers(table_name.table, nil) + split_qualifiers(table_name.column, nil) 757 else 758 sch, table = schema_and_table(table_name, *args) 759 sch ? [sch, table] : [table] 760 end 761 end
Splits table_name into an array of strings.
ds.split_qualifiers(:s) # ['s'] ds.split_qualifiers(Sequel[:t][:s]) # ['t', 's'] ds.split_qualifiers(Sequel[:d][:t][:s]) # ['d', 't', 's'] ds.split_qualifiers(Sequel.qualify(Sequel[:h][:d], Sequel[:t][:s])) # ['h', 'd', 't', 's']
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# File lib/sequel/dataset/sql.rb 764 def subscript_sql_append(sql, s) 765 case s.expression 766 when Symbol, SQL::Subscript, SQL::Identifier, SQL::QualifiedIdentifier 767 # nothing 768 else 769 wrap_expression = true 770 sql << '(' 771 end 772 literal_append(sql, s.expression) 773 if wrap_expression 774 sql << ')[' 775 else 776 sql << '[' 777 end 778 sub = s.sub 779 if sub.length == 1 && (range = sub.first).is_a?(Range) 780 literal_append(sql, range.begin) 781 sql << ':' 782 e = range.end 783 e -= 1 if range.exclude_end? && e.is_a?(Integer) 784 literal_append(sql, e) 785 else 786 expression_list_append(sql, s.sub) 787 end 788 sql << ']' 789 end
Append literalization of subscripts (SQL array accesses) to SQL string.
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# File lib/sequel/dataset/sql.rb 792 def window_sql_append(sql, opts) 793 raise(Error, 'This dataset does not support window functions') unless supports_window_functions? 794 space = false 795 space_s = ' ' 796 797 sql << '(' 798 799 if window = opts[:window] 800 literal_append(sql, window) 801 space = true 802 end 803 804 if part = opts[:partition] 805 sql << space_s if space 806 sql << "PARTITION BY " 807 expression_list_append(sql, Array(part)) 808 space = true 809 end 810 811 if order = opts[:order] 812 sql << space_s if space 813 sql << "ORDER BY " 814 expression_list_append(sql, Array(order)) 815 space = true 816 end 817 818 if frame = opts[:frame] 819 sql << space_s if space 820 821 if frame.is_a?(String) 822 sql << frame 823 else 824 case frame 825 when :all 826 frame_type = :rows 827 frame_start = :preceding 828 frame_end = :following 829 when :rows, :range, :groups 830 frame_type = frame 831 frame_start = :preceding 832 frame_end = :current 833 when Hash 834 frame_type = frame[:type] 835 unless frame_type == :rows || frame_type == :range || frame_type == :groups 836 raise Error, "invalid window :frame :type option: #{frame_type.inspect}" 837 end 838 unless frame_start = frame[:start] 839 raise Error, "invalid window :frame :start option: #{frame_start.inspect}" 840 end 841 frame_end = frame[:end] 842 frame_exclude = frame[:exclude] 843 else 844 raise Error, "invalid window :frame option: #{frame.inspect}" 845 end 846 847 sql << frame_type.to_s.upcase << " " 848 sql << 'BETWEEN ' if frame_end 849 window_frame_boundary_sql_append(sql, frame_start, :preceding) 850 if frame_end 851 sql << " AND " 852 window_frame_boundary_sql_append(sql, frame_end, :following) 853 end 854 855 if frame_exclude 856 sql << " EXCLUDE " 857 858 case frame_exclude 859 when :current 860 sql << "CURRENT ROW" 861 when :group 862 sql << "GROUP" 863 when :ties 864 sql << "TIES" 865 when :no_others 866 sql << "NO OTHERS" 867 else 868 raise Error, "invalid window :frame :exclude option: #{frame_exclude.inspect}" 869 end 870 end 871 end 872 end 873 874 sql << ')' 875 end
Append literalization of windows (for window functions) to SQL string.
Protected Instance Methods
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# File lib/sequel/dataset/sql.rb 881 def compound_from_self 882 (@opts[:sql] || @opts[:limit] || @opts[:order] || @opts[:offset]) ? from_self : self 883 end
Return a from_self dataset if an order or limit is specified, so it works as expected with UNION, EXCEPT, and INTERSECT clauses.
Private Instance Methods
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# File lib/sequel/dataset/sql.rb 1075 def _check_modification_allowed!(modifying_joins_supported) 1076 raise(InvalidOperation, "Grouped datasets cannot be modified") if opts[:group] 1077 raise(InvalidOperation, "Joined datasets cannot be modified") if !modifying_joins_supported && joined_dataset? 1078 end
Internals of the check_*_allowed! methods
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# File lib/sequel/dataset/sql.rb 1290 def _insert_columns_sql(sql, columns) 1291 if columns && !columns.empty? 1292 sql << ' (' 1293 identifier_list_append(sql, columns) 1294 sql << ')' 1295 end 1296 end
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# File lib/sequel/dataset/sql.rb 1312 def _insert_values_sql(sql, values) 1313 case values 1314 when Array 1315 if values.empty? 1316 sql << " DEFAULT VALUES" 1317 else 1318 sql << " VALUES " 1319 literal_append(sql, values) 1320 end 1321 when Dataset 1322 sql << ' ' 1323 subselect_sql_append(sql, values) 1324 when LiteralString 1325 sql << ' ' << values 1326 else 1327 raise Error, "Unsupported INSERT values type, should be an Array or Dataset: #{values.inspect}" 1328 end 1329 end
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# File lib/sequel/dataset/sql.rb 900 def _merge_delete_sql(sql, data) 901 sql << " THEN DELETE" 902 end
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# File lib/sequel/dataset/sql.rb 888 def _merge_insert_sql(sql, data) 889 sql << " THEN INSERT" 890 columns, values = _parse_insert_sql_args(data[:values]) 891 _insert_columns_sql(sql, columns) 892 _insert_values_sql(sql, values) 893 end
Append the INSERT sql used in a MERGE
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# File lib/sequel/dataset/sql.rb 895 def _merge_update_sql(sql, data) 896 sql << " THEN UPDATE SET " 897 update_sql_values_hash(sql, data[:values]) 898 end
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# File lib/sequel/dataset/sql.rb 939 def _merge_when_conditions_sql(sql, data) 940 if data.has_key?(:conditions) 941 sql << " AND " 942 literal_append(sql, data[:conditions]) 943 end 944 end
Append MERGE WHEN conditions, if there are conditions provided.
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# File lib/sequel/dataset/sql.rb 927 def _merge_when_sql(sql) 928 raise Error, "no WHEN [NOT] MATCHED clauses provided for MERGE" unless merge_when = @opts[:merge_when] 929 merge_when.each do |data| 930 type = data[:type] 931 sql << MERGE_TYPE_SQL[type] 932 type = MERGE_NORMALIZE_TYPE_MAP[type] || type 933 _merge_when_conditions_sql(sql, data) 934 send(:"_merge_#{type}_sql", sql, data) 935 end 936 end
Add the WHEN clauses to the MERGE SQL
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# File lib/sequel/dataset/sql.rb 950 def _parse_insert_sql_args(values) 951 columns = [] 952 953 case values.size 954 when 0 955 values = [] 956 when 1 957 case vals = values[0] 958 when Hash 959 values = [] 960 vals.each do |k,v| 961 columns << k 962 values << v 963 end 964 when Dataset, Array, LiteralString 965 values = vals 966 end 967 when 2 968 if (v0 = values[0]).is_a?(Array) && ((v1 = values[1]).is_a?(Array) || v1.is_a?(Dataset) || v1.is_a?(LiteralString)) 969 columns, values = v0, v1 970 raise(Error, "Different number of values and columns given to insert_sql") if values.is_a?(Array) and columns.length != values.length 971 end 972 end 973 974 [columns, values] 975 end
Parse the values passed to insert_sql, returning columns and values to use for the INSERT. Returned columns is always an array, but can be empty for an INSERT without explicit column references. Returned values can be an array, dataset, or literal string.
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# File lib/sequel/dataset/sql.rb 979 def _truncate_sql(table) 980 "TRUNCATE TABLE #{table}" 981 end
Formats the truncate statement. Assumes the table given has already been literalized.
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# File lib/sequel/dataset/sql.rb 1028 def aggreate_dataset_use_from_self? 1029 options_overlap(COUNT_FROM_SELF_OPTS) 1030 end
Whether to use from_self for an aggregate dataset.
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# File lib/sequel/dataset/sql.rb 1023 def aggregate_dataset 1024 (aggreate_dataset_use_from_self? ? from_self : unordered).naked 1025 end
Clone of this dataset usable in aggregate operations. Does a from_self if dataset contains any parameters that would affect normal aggregation, or just removes an existing order if not. Also removes the row_proc, which isn’t needed for aggregate calculations.
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# File lib/sequel/dataset/sql.rb 984 def alias_alias_symbol(s) 985 case s 986 when Symbol 987 s 988 when String 989 s.to_sym 990 when SQL::Identifier 991 s.value.to_s.to_sym 992 else 993 raise Error, "Invalid alias for alias_alias_symbol: #{s.inspect}" 994 end 995 end
Returns an appropriate symbol for the alias represented by s.
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# File lib/sequel/dataset/sql.rb 1000 def alias_symbol(sym) 1001 case sym 1002 when Symbol 1003 s, t, a = split_symbol(sym) 1004 a || s ? (a || t).to_sym : sym 1005 when String 1006 sym.to_sym 1007 when SQL::Identifier 1008 sym.value.to_s.to_sym 1009 when SQL::QualifiedIdentifier 1010 alias_symbol(sym.column) 1011 when SQL::AliasedExpression 1012 alias_alias_symbol(sym.alias) 1013 else 1014 raise Error, "Invalid alias for alias_symbol: #{sym.inspect}" 1015 end 1016 end
Returns an appropriate alias symbol for the given object, which can be a Symbol, String, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression.
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# File lib/sequel/dataset/sql.rb 1033 def as_sql_append(sql, aliaz, column_aliases=nil) 1034 sql << ' AS ' 1035 quote_identifier_append(sql, aliaz) 1036 if column_aliases 1037 raise Error, "#{db.database_type} does not support derived column lists" unless supports_derived_column_lists? 1038 sql << '(' 1039 derived_column_list_sql_append(sql, column_aliases) 1040 sql << ')' 1041 end 1042 end
Append aliasing expression to SQL string.
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# File lib/sequel/dataset/sql.rb 1045 def cache_sql? 1046 !@opts[:no_cache_sql] && !cache_get(:_no_cache_sql) 1047 end
Don’t allow caching SQL if specifically marked not to.
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# File lib/sequel/dataset/sql.rb 1065 def check_delete_allowed! 1066 _check_modification_allowed!(supports_deleting_joins?) 1067 end
Check whether it is allowed to delete from this dataset.
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# File lib/sequel/dataset/sql.rb 1059 def check_insert_allowed! 1060 _check_modification_allowed!(false) 1061 end
Check whether it is allowed to insert into this dataset.
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# File lib/sequel/dataset/sql.rb 1052 def check_modification_allowed! 1053 # SEQUEL6: Remove 1054 Sequel::Deprecation.deprecate("Dataset#check_modification_allowed!", "Use check_{insert,delete,update,truncation}_allowed! instead") 1055 _check_modification_allowed!(supports_modifying_joins?) 1056 end
Raise an InvalidOperation exception if modification is not allowed for this dataset. Check whether it is allowed to insert into this dataset. Only for backwards compatibility with older external adapters.
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# File lib/sequel/dataset/sql.rb 1081 def check_not_limited!(type) 1082 return if @opts[:skip_limit_check] && type != :truncate 1083 raise InvalidOperation, "Dataset##{type} not supported on datasets with limits or offsets" if opts[:limit] || opts[:offset] 1084 end
Raise error if the dataset uses limits or offsets.
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# File lib/sequel/dataset/sql.rb 1070 def check_update_allowed! 1071 _check_modification_allowed!(supports_updating_joins?) 1072 end
Check whether it is allowed to update this dataset.
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# File lib/sequel/dataset/sql.rb 1088 def column_list_append(sql, columns) 1089 if (columns.nil? || columns.empty?) 1090 sql << '*' 1091 else 1092 expression_list_append(sql, columns) 1093 end 1094 end
Append column list to SQL string. If the column list is empty, a wildcard (*) is appended.
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# File lib/sequel/dataset/sql.rb 1100 def complex_expression_arg_pairs(args) 1101 case args.length 1102 when 1 1103 args[0] 1104 when 2 1105 yield args[0], args[1] 1106 else 1107 args.inject{|m, a| yield(m, a)} 1108 end 1109 end
Yield each pair of arguments to the block, which should return an object representing the SQL expression for those two arguments. For more than two arguments, the first argument to the block will be result of the previous block call.
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# File lib/sequel/dataset/sql.rb 1114 def complex_expression_arg_pairs_append(sql, args, &block) 1115 literal_append(sql, complex_expression_arg_pairs(args, &block)) 1116 end
Append the literalization of the args using complex_expression_arg_pairs to the given SQL string, used when database operator/function is 2-ary where Sequel expression is N-ary.
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# File lib/sequel/dataset/sql.rb 1121 def complex_expression_emulate_append(sql, op, args) 1122 # :nocov: 1123 case op 1124 # :nocov: 1125 when :% 1126 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(:MOD, a, b)} 1127 when :>> 1128 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel./(a, Sequel.function(:power, 2, b))} 1129 when :<< 1130 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.*(a, Sequel.function(:power, 2, b))} 1131 when :&, :|, :^ 1132 f = BITWISE_METHOD_MAP[op] 1133 complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(f, a, b)} 1134 when :'B~' 1135 sql << "((0 - " 1136 literal_append(sql, args[0]) 1137 sql << ") - 1)" 1138 end 1139 end
Append literalization of complex expression to SQL string, for operators unsupported by some databases. Used by adapters for databases that don’t support the operators natively.
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# File lib/sequel/dataset/sql.rb 1142 def compound_dataset_sql_append(sql, ds) 1143 subselect_sql_append(sql, ds) 1144 end
Append literalization of dataset used in UNION/INTERSECT/EXCEPT clause to SQL string.
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# File lib/sequel/dataset/sql.rb 1147 def dataset_alias(number) 1148 :"t#{number}" 1149 end
The alias to use for datasets, takes a number to make sure the name is unique.
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# File lib/sequel/dataset/sql.rb 1152 def default_time_format 1153 "'%H:%M:%S.%6N'" 1154 end
The strftime format to use when literalizing time (Sequel::SQLTime) values.
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# File lib/sequel/dataset/sql.rb 1157 def default_timestamp_format 1158 "'%Y-%m-%d %H:%M:%S.%6N'" 1159 end
The strftime format to use when literalizing timestamp (Time/DateTime) values.
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# File lib/sequel/dataset/sql.rb 1161 def delete_delete_sql(sql) 1162 sql << 'DELETE' 1163 end
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# File lib/sequel/dataset/sql.rb 1165 def delete_from_sql(sql) 1166 if f = @opts[:from] 1167 sql << ' FROM ' 1168 source_list_append(sql, f) 1169 end 1170 end
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# File lib/sequel/dataset/sql.rb 1173 def derived_column_list_sql_append(sql, column_aliases) 1174 identifier_list_append(sql, column_aliases) 1175 end
Append the column aliases to the SQL.
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# File lib/sequel/dataset/sql.rb 1178 def disable_sql_caching! 1179 cache_set(:_no_cache_sql, true) 1180 end
Disable caching of SQL for the current dataset
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# File lib/sequel/dataset/sql.rb 1222 def empty_array_value(op, cols) 1223 {1 => ((op == :IN) ? 0 : 1)} 1224 end
An expression for how to handle an empty array lookup.
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# File lib/sequel/dataset/sql.rb 1184 def empty_from_sql 1185 nil 1186 end
An SQL FROM clause to use in SELECT statements where the dataset has no from tables.
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# File lib/sequel/dataset/sql.rb 1190 def emulate_function?(name) 1191 false 1192 end
Whether to emulate the function with the given name. This should only be true if the emulation goes beyond choosing a function with a different name.
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# File lib/sequel/dataset/sql.rb 1196 def expression_list_append(sql, columns) 1197 c = false 1198 co = ', ' 1199 columns.each do |col| 1200 sql << co if c 1201 literal_append(sql, col) 1202 c ||= true 1203 end 1204 end
Append literalization of array of expressions to SQL string, separating them with commas.
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# File lib/sequel/dataset/sql.rb 1227 def format_timestamp(v) 1228 db.from_application_timestamp(v).strftime(default_timestamp_format) 1229 end
Format the timestamp based on the default_timestamp_format.
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# File lib/sequel/dataset/sql.rb 1235 def format_timestamp_usec(usec, ts=timestamp_precision) 1236 # SEQUEL6: Remove 1237 unless ts == 6 1238 usec = usec/(10 ** (6 - ts)) 1239 end 1240 sprintf(".%0#{ts}d", usec) 1241 end
Return the SQL timestamp fragment to use for the fractional time part. Should start with the decimal point. Uses 6 decimal places by default.
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# File lib/sequel/dataset/sql.rb 1207 def grouping_element_list_append(sql, columns) 1208 c = false 1209 co = ', ' 1210 columns.each do |col| 1211 sql << co if c 1212 if col.is_a?(Array) && col.empty? 1213 sql << '()' 1214 else 1215 literal_append(sql, Array(col)) 1216 end 1217 c ||= true 1218 end 1219 end
Append literalization of array of grouping elements to SQL string, seperating them with commas.
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# File lib/sequel/dataset/sql.rb 1246 def identifier_append(sql, v) 1247 if v.is_a?(String) 1248 case v 1249 when LiteralString 1250 sql << v 1251 when SQL::Blob 1252 literal_append(sql, v) 1253 else 1254 quote_identifier_append(sql, v) 1255 end 1256 else 1257 literal_append(sql, v) 1258 end 1259 end
Append literalization of identifier to SQL string, considering regular strings as SQL identifiers instead of SQL strings.
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# File lib/sequel/dataset/sql.rb 1262 def identifier_list_append(sql, args) 1263 c = false 1264 comma = ', ' 1265 args.each do |a| 1266 sql << comma if c 1267 identifier_append(sql, a) 1268 c ||= true 1269 end 1270 end
Append literalization of array of identifiers to SQL string.
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# File lib/sequel/dataset/sql.rb 1273 def input_identifier(v) 1274 v.to_s.upcase 1275 end
Upcase identifiers by default when inputting them into the database.
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# File lib/sequel/dataset/sql.rb 1286 def insert_columns_sql(sql) 1287 _insert_columns_sql(sql, opts[:columns]) 1288 end
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# File lib/sequel/dataset/sql.rb 1300 def insert_empty_columns_values 1301 [[columns.last], [DEFAULT]] 1302 end
The columns and values to use for an empty insert if the database doesn’t support INSERT with DEFAULT VALUES.
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# File lib/sequel/dataset/sql.rb 1304 def insert_insert_sql(sql) 1305 sql << "INSERT" 1306 end
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# File lib/sequel/dataset/sql.rb 1277 def insert_into_sql(sql) 1278 sql << " INTO " 1279 if (f = @opts[:from]) && f.length == 1 1280 identifier_append(sql, unaliased_identifier(f.first)) 1281 else 1282 source_list_append(sql, f) 1283 end 1284 end
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# File lib/sequel/dataset/sql.rb 1331 def insert_returning_sql(sql) 1332 if opts.has_key?(:returning) 1333 sql << " RETURNING " 1334 column_list_append(sql, Array(opts[:returning])) 1335 end 1336 end
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# File lib/sequel/dataset/sql.rb 1308 def insert_values_sql(sql) 1309 _insert_values_sql(sql, opts[:values]) 1310 end
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# File lib/sequel/dataset/sql.rb 1342 def join_type_sql(join_type) 1343 "#{join_type.to_s.tr('_', ' ').upcase} JOIN" 1344 end
SQL fragment specifying a JOIN type, converts underscores to spaces and upcases.
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# File lib/sequel/dataset/sql.rb 1347 def join_using_clause_using_sql_append(sql, using_columns) 1348 sql << ' USING (' 1349 column_list_append(sql, using_columns) 1350 sql << ')' 1351 end
Append USING clause for JOIN USING
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# File lib/sequel/dataset/sql.rb 1355 def literal_array_append(sql, v) 1356 if Sequel.condition_specifier?(v) 1357 literal_expression_append(sql, SQL::BooleanExpression.from_value_pairs(v)) 1358 else 1359 array_sql_append(sql, v) 1360 end 1361 end
Append a literalization of the array to SQL string. Treats as an expression if an array of all two pairs, or as a SQL array otherwise.
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# File lib/sequel/dataset/sql.rb 1364 def literal_big_decimal(v) 1365 d = v.to_s("F") 1366 v.nan? || v.infinite? ? "'#{d}'" : d 1367 end
SQL fragment for BigDecimal
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# File lib/sequel/dataset/sql.rb 1375 def literal_dataset_append(sql, v) 1376 sql << 'LATERAL ' if v.opts[:lateral] 1377 sql << '(' 1378 subselect_sql_append(sql, v) 1379 sql << ')' 1380 end
Append literalization of dataset to SQL string. Does a subselect inside parantheses.
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# File lib/sequel/dataset/sql.rb 1383 def literal_date(v) 1384 v.strftime("'%Y-%m-%d'") 1385 end
SQL fragment for Date, using the ISO8601 format.
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# File lib/sequel/dataset/sql.rb 1388 def literal_date_append(sql, v) 1389 sql << literal_date(v) 1390 end
Append literalization of date to SQL string.
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# File lib/sequel/dataset/sql.rb 1393 def literal_datetime(v) 1394 format_timestamp(v) 1395 end
SQL fragment for DateTime
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# File lib/sequel/dataset/sql.rb 1398 def literal_datetime_append(sql, v) 1399 sql << literal_datetime(v) 1400 end
Append literalization of DateTime to SQL string.
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# File lib/sequel/dataset/sql.rb 1403 def literal_expression_append(sql, v) 1404 v.to_s_append(self, sql) 1405 end
Append literalization of SQL::Expression to SQL string.
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# File lib/sequel/dataset/sql.rb 1408 def literal_false 1409 "'f'" 1410 end
SQL fragment for false
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# File lib/sequel/dataset/sql.rb 1413 def literal_float(v) 1414 v.to_s 1415 end
SQL fragment for Float
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# File lib/sequel/dataset/sql.rb 1423 def literal_integer(v) 1424 v.to_s 1425 end
SQL fragment for Integer
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# File lib/sequel/dataset/sql.rb 1428 def literal_literal_string_append(sql, v) 1429 sql << v 1430 end
Append string to SQL string.
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# File lib/sequel/dataset/sql.rb 1433 def literal_nil 1434 "NULL" 1435 end
SQL fragment for nil
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# File lib/sequel/dataset/sql.rb 1441 def literal_other_append(sql, v) 1442 if v.respond_to?(:sql_literal_append) 1443 v.sql_literal_append(self, sql) 1444 elsif v.respond_to?(:sql_literal) 1445 sql << v.sql_literal(self) 1446 else 1447 raise Error, "can't express #{v.inspect} as a SQL literal" 1448 end 1449 1450 if !v.respond_to?(:sql_literal_allow_caching?) || !v.sql_literal_allow_caching?(self) 1451 # We can't be sure if v will always literalize to the same SQL, so 1452 # don't cache SQL for a dataset that uses this. 1453 disable_sql_caching! 1454 end 1455 end
Append a literalization of the object to the given SQL string. Calls sql_literal_append if object responds to it, otherwise calls sql_literal if object responds to it, otherwise raises an error. If a database specific type is allowed, this should be overriden in a subclass.
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# File lib/sequel/dataset/sql.rb 1464 def literal_sqltime(v) 1465 v.strftime(default_time_format) 1466 end
SQL fragment for Sequel::SQLTime, containing just the time part
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# File lib/sequel/dataset/sql.rb 1469 def literal_sqltime_append(sql, v) 1470 sql << literal_sqltime(v) 1471 end
Append literalization of Sequel::SQLTime to SQL string.
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# File lib/sequel/dataset/sql.rb 1474 def literal_string_append(sql, v) 1475 sql << "'" << v.gsub("'", "''") << "'" 1476 end
Append literalization of string to SQL string.
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# File lib/sequel/dataset/sql.rb 1479 def literal_symbol_append(sql, v) 1480 c_table, column, c_alias = split_symbol(v) 1481 if c_table 1482 quote_identifier_append(sql, c_table) 1483 sql << '.' 1484 end 1485 quote_identifier_append(sql, column) 1486 as_sql_append(sql, c_alias) if c_alias 1487 end
Append literalization of symbol to SQL string.
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# File lib/sequel/dataset/sql.rb 1490 def literal_time(v) 1491 format_timestamp(v) 1492 end
SQL fragment for Time
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# File lib/sequel/dataset/sql.rb 1495 def literal_time_append(sql, v) 1496 sql << literal_time(v) 1497 end
Append literalization of Time to SQL string.
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# File lib/sequel/dataset/sql.rb 1500 def literal_true 1501 "'t'" 1502 end
SQL fragment for true
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# File lib/sequel/dataset/sql.rb 1508 def multi_insert_sql_strategy 1509 :separate 1510 end
What strategy to use for import/multi_insert. While SQL-92 defaults to allowing multiple rows in a VALUES clause, there are enough databases that don’t allow that that it can’t be the default. Use separate queries by default, which works everywhere.
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# File lib/sequel/dataset/sql.rb 1514 def native_function_name(emulated_function) 1515 emulated_function 1516 end
Get the native function name given the emulated function name.
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# File lib/sequel/dataset/sql.rb 1520 def qualified_column_name(column, table) 1521 if column.is_a?(Symbol) 1522 c_table, column, _ = split_symbol(column) 1523 unless c_table 1524 case table 1525 when Symbol 1526 schema, table, t_alias = split_symbol(table) 1527 t_alias ||= Sequel::SQL::QualifiedIdentifier.new(schema, table) if schema 1528 when Sequel::SQL::AliasedExpression 1529 t_alias = table.alias 1530 end 1531 c_table = t_alias || table 1532 end 1533 ::Sequel::SQL::QualifiedIdentifier.new(c_table, column) 1534 else 1535 column 1536 end 1537 end
Returns a qualified column name (including a table name) if the column name isn’t already qualified.
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# File lib/sequel/dataset/sql.rb 1540 def qualified_expression(e, table) 1541 Qualifier.new(table).transform(e) 1542 end
Qualify the given expression to the given table.
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# File lib/sequel/dataset/sql.rb 1544 def select_columns_sql(sql) 1545 sql << ' ' 1546 column_list_append(sql, @opts[:select]) 1547 end
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# File lib/sequel/dataset/sql.rb 1563 def select_compounds_sql(sql) 1564 return unless c = @opts[:compounds] 1565 c.each do |type, dataset, all| 1566 sql << ' ' << type.to_s.upcase 1567 sql << ' ALL' if all 1568 sql << ' ' 1569 compound_dataset_sql_append(sql, dataset) 1570 end 1571 end
Modify the sql to add a dataset to the via an EXCEPT, INTERSECT, or UNION clause. This uses a subselect for the compound datasets used, because using parantheses doesn’t work on all databases.
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# File lib/sequel/dataset/sql.rb 1549 def select_distinct_sql(sql) 1550 if distinct = @opts[:distinct] 1551 sql << " DISTINCT" 1552 unless distinct.empty? 1553 sql << " ON (" 1554 expression_list_append(sql, distinct) 1555 sql << ')' 1556 end 1557 end 1558 end
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# File lib/sequel/dataset/sql.rb 1573 def select_from_sql(sql) 1574 if f = @opts[:from] 1575 sql << ' FROM ' 1576 source_list_append(sql, f) 1577 elsif f = empty_from_sql 1578 sql << f 1579 end 1580 end
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# File lib/sequel/dataset/sql.rb 1582 def select_group_sql(sql) 1583 if group = @opts[:group] 1584 sql << " GROUP BY " 1585 if go = @opts[:group_options] 1586 if go == :"grouping sets" 1587 sql << go.to_s.upcase << '(' 1588 grouping_element_list_append(sql, group) 1589 sql << ')' 1590 elsif uses_with_rollup? 1591 expression_list_append(sql, group) 1592 sql << " WITH " << go.to_s.upcase 1593 else 1594 sql << go.to_s.upcase << '(' 1595 expression_list_append(sql, group) 1596 sql << ')' 1597 end 1598 else 1599 expression_list_append(sql, group) 1600 end 1601 end 1602 end
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# File lib/sequel/dataset/sql.rb 1604 def select_having_sql(sql) 1605 if having = @opts[:having] 1606 sql << " HAVING " 1607 literal_append(sql, having) 1608 end 1609 end
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# File lib/sequel/dataset/sql.rb 1611 def select_join_sql(sql) 1612 if js = @opts[:join] 1613 js.each{|j| literal_append(sql, j)} 1614 end 1615 end
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# File lib/sequel/dataset/sql.rb 1617 def select_limit_sql(sql) 1618 if l = @opts[:limit] 1619 sql << " LIMIT " 1620 literal_append(sql, l) 1621 if o = @opts[:offset] 1622 sql << " OFFSET " 1623 literal_append(sql, o) 1624 end 1625 elsif @opts[:offset] 1626 select_only_offset_sql(sql) 1627 end 1628 end
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# File lib/sequel/dataset/sql.rb 1630 def select_lock_sql(sql) 1631 case l = @opts[:lock] 1632 when :update 1633 sql << ' FOR UPDATE' 1634 when String 1635 sql << ' ' << l 1636 end 1637 end
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# File lib/sequel/dataset/sql.rb 1642 def select_only_offset_sql(sql) 1643 sql << " OFFSET " 1644 literal_append(sql, @opts[:offset]) 1645 end
Used only if there is an offset and no limit, making it easier to override in the adapter, as many databases do not support just a plain offset with no limit.
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# File lib/sequel/dataset/sql.rb 1647 def select_order_sql(sql) 1648 if o = @opts[:order] 1649 sql << " ORDER BY " 1650 expression_list_append(sql, o) 1651 end 1652 end
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# File lib/sequel/dataset/sql.rb 1656 def select_select_sql(sql) 1657 sql << 'SELECT' 1658 end
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# File lib/sequel/dataset/sql.rb 1660 def select_where_sql(sql) 1661 if w = @opts[:where] 1662 sql << " WHERE " 1663 literal_append(sql, w) 1664 end 1665 end
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# File lib/sequel/dataset/sql.rb 1669 def select_window_sql(sql) 1670 if ws = @opts[:window] 1671 sql << " WINDOW " 1672 c = false 1673 co = ', ' 1674 as = ' AS ' 1675 ws.map do |name, window| 1676 sql << co if c 1677 literal_append(sql, name) 1678 sql << as 1679 literal_append(sql, window) 1680 c ||= true 1681 end 1682 end 1683 end
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# File lib/sequel/dataset/sql.rb 1685 def select_with_sql(sql) 1686 return unless supports_cte? 1687 ctes = opts[:with] 1688 return if !ctes || ctes.empty? 1689 sql << select_with_sql_base 1690 c = false 1691 comma = ', ' 1692 ctes.each do |cte| 1693 sql << comma if c 1694 select_with_sql_cte(sql, cte) 1695 c ||= true 1696 end 1697 sql << ' ' 1698 end
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# File lib/sequel/dataset/sql.rb 1703 def select_with_sql_base 1704 "WITH " 1705 end
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# File lib/sequel/dataset/sql.rb 1707 def select_with_sql_cte(sql, cte) 1708 select_with_sql_prefix(sql, cte) 1709 literal_dataset_append(sql, cte[:dataset]) 1710 end
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# File lib/sequel/dataset/sql.rb 1712 def select_with_sql_prefix(sql, w) 1713 quote_identifier_append(sql, w[:name]) 1714 if args = w[:args] 1715 sql << '(' 1716 identifier_list_append(sql, args) 1717 sql << ')' 1718 end 1719 sql << ' AS ' 1720 1721 case w[:materialized] 1722 when true 1723 sql << "MATERIALIZED " 1724 when false 1725 sql << "NOT MATERIALIZED " 1726 end 1727 end
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# File lib/sequel/dataset/sql.rb 1730 def skip_symbol_cache? 1731 @opts[:skip_symbol_cache] 1732 end
Whether the symbol cache should be skipped when literalizing the dataset
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# File lib/sequel/dataset/sql.rb 1736 def source_list_append(sql, sources) 1737 raise(Error, 'No source specified for query') if sources.nil? || sources == [] 1738 identifier_list_append(sql, sources) 1739 end
Append literalization of array of sources/tables to SQL string, raising an Error if there are no sources.
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# File lib/sequel/dataset/sql.rb 1742 def split_symbol(sym) 1743 Sequel.split_symbol(sym) 1744 end
Delegate to Sequel.split_symbol.
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# File lib/sequel/dataset/sql.rb 1748 def sql_string_origin 1749 String.new 1750 end
The string that is appended to to create the SQL query, the empty string by default.
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# File lib/sequel/dataset/sql.rb 1754 def sqltime_precision 1755 timestamp_precision 1756 end
The precision to use for SQLTime instances (time column values without dates). Defaults to timestamp_precision.
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# File lib/sequel/dataset/sql.rb 1762 def static_sql(sql) 1763 if append_sql = @opts[:append_sql] 1764 if sql.is_a?(String) 1765 append_sql << sql 1766 else 1767 literal_append(append_sql, sql) 1768 end 1769 else 1770 if sql.is_a?(String) 1771 sql 1772 else 1773 literal(sql) 1774 end 1775 end 1776 end
SQL to use if this dataset uses static SQL. Since static SQL can be a PlaceholderLiteralString in addition to a String, we literalize nonstrings. If there is an append_sql for this dataset, append to that SQL instead of returning the value.
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# File lib/sequel/dataset/sql.rb 1779 def subselect_sql_append(sql, ds) 1780 sds = subselect_sql_dataset(sql, ds) 1781 subselect_sql_append_sql(sql, sds) 1782 unless sds.send(:cache_sql?) 1783 # If subquery dataset does not allow caching SQL, 1784 # then this dataset should not allow caching SQL. 1785 disable_sql_caching! 1786 end 1787 end
Append literalization of the subselect to SQL string.
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# File lib/sequel/dataset/sql.rb 1793 def subselect_sql_append_sql(sql, ds) 1794 ds.sql 1795 end
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# File lib/sequel/dataset/sql.rb 1789 def subselect_sql_dataset(sql, ds) 1790 ds.clone(:append_sql=>sql) 1791 end
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# File lib/sequel/dataset/sql.rb 1798 def timestamp_precision 1799 supports_timestamp_usecs? ? 6 : 0 1800 end
The number of decimal digits of precision to use in timestamps.
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# File lib/sequel/dataset/sql.rb 1808 def update_set_sql(sql) 1809 sql << ' SET ' 1810 values = @opts[:values] 1811 if values.is_a?(Hash) 1812 update_sql_values_hash(sql, values) 1813 else 1814 sql << values 1815 end 1816 end
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# File lib/sequel/dataset/sql.rb 1818 def update_sql_values_hash(sql, values) 1819 c = false 1820 eq = ' = ' 1821 values.each do |k, v| 1822 sql << ', ' if c 1823 if k.is_a?(String) && !k.is_a?(LiteralString) 1824 quote_identifier_append(sql, k) 1825 else 1826 literal_append(sql, k) 1827 end 1828 sql << eq 1829 literal_append(sql, v) 1830 c ||= true 1831 end 1832 end
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# File lib/sequel/dataset/sql.rb 1802 def update_table_sql(sql) 1803 sql << ' ' 1804 source_list_append(sql, @opts[:from]) 1805 select_join_sql(sql) if supports_modifying_joins? 1806 end
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# File lib/sequel/dataset/sql.rb 1834 def update_update_sql(sql) 1835 sql << 'UPDATE' 1836 end
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# File lib/sequel/dataset/sql.rb 1838 def window_frame_boundary_sql_append(sql, boundary, direction) 1839 case boundary 1840 when :current 1841 sql << "CURRENT ROW" 1842 when :preceding 1843 sql << "UNBOUNDED PRECEDING" 1844 when :following 1845 sql << "UNBOUNDED FOLLOWING" 1846 else 1847 if boundary.is_a?(Array) 1848 offset, direction = boundary 1849 unless boundary.length == 2 && (direction == :preceding || direction == :following) 1850 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1851 end 1852 else 1853 offset = boundary 1854 end 1855 1856 case offset 1857 when Numeric, String, SQL::Cast 1858 # nothing 1859 else 1860 raise Error, "invalid window :frame boundary (:start or :end) option: #{boundary.inspect}" 1861 end 1862 1863 literal_append(sql, offset) 1864 sql << (direction == :preceding ? " PRECEDING" : " FOLLOWING") 1865 end 1866 end