class Sequel::IntegerMigrator

    # File lib/sequel/extensions/migration.rb
550 def initialize(db, directory, opts=OPTS)
551   super
552   @current = opts[:current] || current_migration_version
553 
554   latest_version = latest_migration_version
555   @target = if opts[:target]
556     opts[:target]
557   elsif opts[:relative]
558     @current + opts[:relative]
559   else
560     latest_version
561   end
562 
563   raise(Error, "No target and/or latest version available, probably because no migration files found or filenames don't follow the migration filename convention") unless target && latest_version
564 
565   if @target > latest_version
566     @target = latest_version
567   elsif @target < 0
568     @target = 0
569   end
570 
571   @direction = current < target ? :up : :down
572 
573   if @direction == :down && @current >= @files.length && !@allow_missing_migration_files
574     raise Migrator::Error, "Missing migration version(s) needed to migrate down to target version (current: #{current}, target: #{target})"
575   end
576 
577   @migrations = get_migrations
578 end

    # File lib/sequel/extensions/migration.rb
581 def is_current?
582   current_migration_version == target
583 end

    # File lib/sequel/extensions/migration.rb
586 def run
587   migrations.zip(version_numbers).each do |m, v|
588     timer = Sequel.start_timer
589     db.log_info("Begin applying migration version #{v}, direction: #{direction}")
590     checked_transaction(m) do
591       m.apply(db, direction)
592       set_migration_version(up? ? v : v-1)
593     end
594     db.log_info("Finished applying migration version #{v}, direction: #{direction}, took #{sprintf('%0.6f', Sequel.elapsed_seconds_since(timer))} seconds")
595   end
596   
597   target
598 end

    # File lib/sequel/extensions/migration.rb
604 def current_migration_version
605   ds.get(column) || 0
606 end

    # File lib/sequel/extensions/migration.rb
609 def default_schema_column
610   :version
611 end

    # File lib/sequel/extensions/migration.rb
614 def default_schema_table
615   :schema_info
616 end

    # File lib/sequel/extensions/migration.rb
619 def get_migration_files
620   files = []
621   Dir.new(directory).each do |file|
622     next unless MIGRATION_FILE_PATTERN.match(file)
623     version = migration_version_from_file(file)
624     if version >= 20000101
625       raise Migrator::Error, "Migration number too large, must use TimestampMigrator: #{file}"
626     end
627     raise(Error, "Duplicate migration version: #{version}") if files[version]
628     files[version] = File.join(directory, file)
629   end
630   1.upto(files.length - 1){|i| raise(Error, "Missing migration version: #{i}") unless files[i]} unless @allow_missing_migration_files
631   files
632 end

    # File lib/sequel/extensions/migration.rb
636 def get_migrations
637   version_numbers.map{|n| load_migration_file(files[n])}
638 end

    # File lib/sequel/extensions/migration.rb
641 def latest_migration_version
642   l = files.last
643   l ? migration_version_from_file(File.basename(l)) : nil
644 end

    # File lib/sequel/extensions/migration.rb
648 def schema_dataset
649   c = column
650   ds = db.from(table)
651   db.create_table?(table){Integer c, :default=>0, :null=>false}
652   unless ds.columns.include?(c)
653     db.alter_table(table){add_column c, Integer, :default=>0, :null=>false}
654   end
655   ds.insert(c=>0) if ds.empty?
656   raise(Error, "More than 1 row in migrator table") if ds.count > 1
657   ds
658 end

    # File lib/sequel/extensions/migration.rb
661 def set_migration_version(version)
662   ds.update(column=>version)
663 end

    # File lib/sequel/extensions/migration.rb
666 def up?
667   direction == :up
668 end

    # File lib/sequel/extensions/migration.rb
673 def version_numbers
674   @version_numbers ||= begin
675     versions = files.
676       compact.
677       map{|f| migration_version_from_file(File.basename(f))}.
678       select{|v| up? ? (v > current && v <= target) : (v <= current && v > target)}.
679       sort
680     versions.reverse! unless up?
681     versions
682   end
683 end