class Sequel::IntegerMigrator

    # File lib/sequel/extensions/migration.rb
555 def initialize(db, directory, opts=OPTS)
556   super
557   @current = opts[:current] || current_migration_version
558 
559   latest_version = latest_migration_version
560   @target = if opts[:target]
561     opts[:target]
562   elsif opts[:relative]
563     @current + opts[:relative]
564   else
565     latest_version
566   end
567 
568   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
569 
570   if @target > latest_version
571     @target = latest_version
572   elsif @target < 0
573     @target = 0
574   end
575 
576   @direction = current < target ? :up : :down
577 
578   if @direction == :down && @current >= @files.length && !@allow_missing_migration_files
579     raise Migrator::Error, "Missing migration version(s) needed to migrate down to target version (current: #{current}, target: #{target})"
580   end
581 
582   @migrations = get_migrations
583 end

    # File lib/sequel/extensions/migration.rb
586 def is_current?
587   current_migration_version == target
588 end

    # File lib/sequel/extensions/migration.rb
591 def run
592   migrations.zip(version_numbers).each do |m, v|
593     timer = Sequel.start_timer
594     db.log_info("Begin applying migration version #{v}, direction: #{direction}")
595     checked_transaction(m) do
596       m.apply(db, direction)
597       set_migration_version(up? ? v : v-1)
598     end
599     db.log_info("Finished applying migration version #{v}, direction: #{direction}, took #{sprintf('%0.6f', Sequel.elapsed_seconds_since(timer))} seconds")
600   end
601   
602   target
603 end

    # File lib/sequel/extensions/migration.rb
609 def current_migration_version
610   ds.get(column) || 0
611 end

    # File lib/sequel/extensions/migration.rb
614 def default_schema_column
615   :version
616 end

    # File lib/sequel/extensions/migration.rb
619 def default_schema_table
620   :schema_info
621 end

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

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

    # File lib/sequel/extensions/migration.rb
646 def latest_migration_version
647   l = files.last
648   l ? migration_version_from_file(File.basename(l)) : nil
649 end

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

    # File lib/sequel/extensions/migration.rb
666 def set_migration_version(version)
667   ds.update(column=>version)
668 end

    # File lib/sequel/extensions/migration.rb
671 def up?
672   direction == :up
673 end

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