diff options
Diffstat (limited to 'activerecord/lib/active_record/migration.rb')
| -rw-r--r-- | activerecord/lib/active_record/migration.rb | 152 |
1 files changed, 119 insertions, 33 deletions
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb index 4cfda302ea..5bdb7213cd 100644 --- a/activerecord/lib/active_record/migration.rb +++ b/activerecord/lib/active_record/migration.rb @@ -9,40 +9,128 @@ module ActiveRecord end end - # Exception that can be raised to stop migrations from going backwards. + # Exception that can be raised to stop migrations from being rolled back. + # For example the following migration is not reversible. + # Rolling back this migration will raise an ActiveRecord::IrreversibleMigration error. + # + # class IrreversibleMigrationExample < ActiveRecord::Migration + # def change + # create_table :distributors do |t| + # t.string :zipcode + # end + # + # execute <<-SQL + # ALTER TABLE distributors + # ADD CONSTRAINT zipchk + # CHECK (char_length(zipcode) = 5) NO INHERIT; + # SQL + # end + # end + # + # There are two ways to mitigate this problem. + # + # 1. Define <tt>#up</tt> and <tt>#down</tt> methods instead of <tt>#change</tt>: + # + # class ReversibleMigrationExample < ActiveRecord::Migration + # def up + # create_table :distributors do |t| + # t.string :zipcode + # end + # + # execute <<-SQL + # ALTER TABLE distributors + # ADD CONSTRAINT zipchk + # CHECK (char_length(zipcode) = 5) NO INHERIT; + # SQL + # end + # + # def down + # execute <<-SQL + # ALTER TABLE distributors + # DROP CONSTRAINT zipchk + # SQL + # + # drop_table :distributors + # end + # end + # + # 2. Use the #reversible method in <tt>#change</tt> method: + # + # class ReversibleMigrationExample < ActiveRecord::Migration + # def change + # create_table :distributors do |t| + # t.string :zipcode + # end + # + # reversible do |dir| + # dir.up do + # execute <<-SQL + # ALTER TABLE distributors + # ADD CONSTRAINT zipchk + # CHECK (char_length(zipcode) = 5) NO INHERIT; + # SQL + # end + # + # dir.down do + # execute <<-SQL + # ALTER TABLE distributors + # DROP CONSTRAINT zipchk + # SQL + # end + # end + # end + # end class IrreversibleMigration < MigrationError end class DuplicateMigrationVersionError < MigrationError#:nodoc: - def initialize(version) - super("Multiple migrations have the version number #{version}") + def initialize(version = nil) + if version + super("Multiple migrations have the version number #{version}.") + else + super("Duplicate migration version error.") + end end end class DuplicateMigrationNameError < MigrationError#:nodoc: - def initialize(name) - super("Multiple migrations have the name #{name}") + def initialize(name = nil) + if name + super("Multiple migrations have the name #{name}.") + else + super("Duplicate migration name.") + end end end class UnknownMigrationVersionError < MigrationError #:nodoc: - def initialize(version) - super("No migration with version number #{version}") + def initialize(version = nil) + if version + super("No migration with version number #{version}.") + else + super("Unknown migration version.") + end end end class IllegalMigrationNameError < MigrationError#:nodoc: - def initialize(name) - super("Illegal name for migration file: #{name}\n\t(only lower case letters, numbers, and '_' allowed)") + def initialize(name = nil) + if name + super("Illegal name for migration file: #{name}\n\t(only lower case letters, numbers, and '_' allowed).") + else + super("Illegal name for migration.") + end end end class PendingMigrationError < MigrationError#:nodoc: - def initialize - if defined?(Rails.env) - super("Migrations are pending. To resolve this issue, run:\n\n\tbin/rake db:migrate RAILS_ENV=#{::Rails.env}") + def initialize(message = nil) + if !message && defined?(Rails.env) + super("Migrations are pending. To resolve this issue, run:\n\n\tbin/rake db:migrate RAILS_ENV=#{::Rails.env}.") + elsif !message + super("Migrations are pending. To resolve this issue, run:\n\n\tbin/rake db:migrate.") else - super("Migrations are pending. To resolve this issue, run:\n\n\tbin/rake db:migrate") + super end end end @@ -168,7 +256,7 @@ module ActiveRecord # # rails generate migration add_fieldname_to_tablename fieldname:string # - # This will generate the file <tt>timestamp_add_fieldname_to_tablename</tt>, which will look like this: + # This will generate the file <tt>timestamp_add_fieldname_to_tablename.rb</tt>, which will look like this: # class AddFieldnameToTablename < ActiveRecord::Migration # def change # add_column :tablenames, :fieldname, :string @@ -376,6 +464,7 @@ module ActiveRecord attr_accessor :delegate # :nodoc: attr_accessor :disable_ddl_transaction # :nodoc: + # Raises <tt>ActiveRecord::PendingMigrationError</tt> error if any migrations are pending. def check_pending!(connection = Base.connection) raise ActiveRecord::PendingMigrationError if ActiveRecord::Migrator.needs_migration?(connection) end @@ -408,7 +497,10 @@ module ActiveRecord new.migrate direction end - # Disable DDL transactions for this migration. + # Disable the transaction wrapping this migration. + # You can still create your own transactions even after calling #disable_ddl_transaction! + # + # For more details read the {"Transactional Migrations" section above}[rdoc-ref:Migration]. def disable_ddl_transaction! @disable_ddl_transaction = true end @@ -455,7 +547,7 @@ module ActiveRecord # Or equivalently, if +TenderloveMigration+ is defined as in the # documentation for Migration: # - # require_relative '2012121212_tenderlove_migration' + # require_relative '20121212123456_tenderlove_migration' # # class FixupTLMigration < ActiveRecord::Migration # def change @@ -471,13 +563,13 @@ module ActiveRecord def revert(*migration_classes) run(*migration_classes.reverse, revert: true) unless migration_classes.empty? if block_given? - if @connection.respond_to? :revert - @connection.revert { yield } + if connection.respond_to? :revert + connection.revert { yield } else - recorder = CommandRecorder.new(@connection) + recorder = CommandRecorder.new(connection) @connection = recorder suppress_messages do - @connection.revert { yield } + connection.revert { yield } end @connection = recorder.delegate recorder.commands.each do |cmd, args, block| @@ -488,7 +580,7 @@ module ActiveRecord end def reverting? - @connection.respond_to?(:reverting) && @connection.reverting + connection.respond_to?(:reverting) && connection.reverting end class ReversibleBlockHelper < Struct.new(:reverting) # :nodoc: @@ -545,7 +637,7 @@ module ActiveRecord revert { run(*migration_classes, direction: dir, revert: true) } else migration_classes.each do |migration_class| - migration_class.new.exec_migration(@connection, dir) + migration_class.new.exec_migration(connection, dir) end end end @@ -637,7 +729,7 @@ module ActiveRecord arg_list = arguments.map(&:inspect) * ', ' say_with_time "#{method}(#{arg_list})" do - unless @connection.respond_to? :revert + unless connection.respond_to? :revert unless arguments.empty? || [:execute, :enable_extension, :disable_extension].include?(method) arguments[0] = proper_table_name(arguments.first, table_name_options) if [:rename_table, :add_foreign_key].include?(method) || @@ -716,7 +808,9 @@ module ActiveRecord end end - def table_name_options(config = ActiveRecord::Base) + # Builds a hash for use in ActiveRecord::Migration#proper_table_name using + # the Active Record object's table_name prefix and suffix + def table_name_options(config = ActiveRecord::Base) #:nodoc: { table_name_prefix: config.table_name_prefix, table_name_suffix: config.table_name_suffix @@ -808,7 +902,7 @@ module ActiveRecord new(:up, migrations, target_version).migrate end - def down(migrations_paths, target_version = nil, &block) + def down(migrations_paths, target_version = nil) migrations = migrations(migrations_paths) migrations.select! { |m| yield m } if block_given? @@ -847,10 +941,6 @@ module ActiveRecord migrations(migrations_paths).any? end - def last_version - last_migration.version - end - def last_migration #:nodoc: migrations(migrations_paths).last || NullMigration.new end @@ -861,10 +951,6 @@ module ActiveRecord Array(@migrations_paths) end - def migrations_path - migrations_paths.first - end - def migrations(paths) paths = Array(paths) |