diff options
Diffstat (limited to 'activerecord/lib/active_record/migration.rb')
-rw-r--r-- | activerecord/lib/active_record/migration.rb | 290 |
1 files changed, 203 insertions, 87 deletions
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb index 7c4dad21a0..c8b96b8de0 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) - 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 @@ -106,17 +194,18 @@ module ActiveRecord # # == Available transformations # + # === Creation + # + # * <tt>create_join_table(table_1, table_2, options)</tt>: Creates a join + # table having its name as the lexical order of the first two + # arguments. See + # ActiveRecord::ConnectionAdapters::SchemaStatements#create_join_table for + # details. # * <tt>create_table(name, options)</tt>: Creates a table called +name+ and # makes the table object available to a block that can then add columns to it, # following the same format as +add_column+. See example above. The options hash # is for fragments like "DEFAULT CHARSET=UTF-8" that are appended to the create # table definition. - # * <tt>drop_table(name)</tt>: Drops the table called +name+. - # * <tt>change_table(name, options)</tt>: Allows to make column alterations to - # the table called +name+. It makes the table object available to a block that - # can then add/remove columns, indexes or foreign keys to it. - # * <tt>rename_table(old_name, new_name)</tt>: Renames the table called +old_name+ - # to +new_name+. # * <tt>add_column(table_name, column_name, type, options)</tt>: Adds a new column # to the table called +table_name+ # named +column_name+ specified to be one of the following types: @@ -127,21 +216,59 @@ module ActiveRecord # Other options include <tt>:limit</tt> and <tt>:null</tt> (e.g. # <tt>{ limit: 50, null: false }</tt>) -- see # ActiveRecord::ConnectionAdapters::TableDefinition#column for details. - # * <tt>rename_column(table_name, column_name, new_column_name)</tt>: Renames - # a column but keeps the type and content. - # * <tt>change_column(table_name, column_name, type, options)</tt>: Changes - # the column to a different type using the same parameters as add_column. - # * <tt>remove_column(table_name, column_name, type, options)</tt>: Removes the column - # named +column_name+ from the table called +table_name+. + # * <tt>add_foreign_key(from_table, to_table, options)</tt>: Adds a new + # foreign key. +from_table+ is the table with the key column, +to_table+ contains + # the referenced primary key. # * <tt>add_index(table_name, column_names, options)</tt>: Adds a new index # with the name of the column. Other options include # <tt>:name</tt>, <tt>:unique</tt> (e.g. # <tt>{ name: 'users_name_index', unique: true }</tt>) and <tt>:order</tt> # (e.g. <tt>{ order: { name: :desc } }</tt>). - # * <tt>remove_index(table_name, column: column_name)</tt>: Removes the index - # specified by +column_name+. + # * <tt>add_reference(:table_name, :reference_name)</tt>: Adds a new column + # +reference_name_id+ by default an integer. See + # ActiveRecord::ConnectionAdapters::SchemaStatements#add_reference for details. + # * <tt>add_timestamps(table_name, options)</tt>: Adds timestamps (+created_at+ + # and +updated_at+) columns to +table_name+. + # + # === Modification + # + # * <tt>change_column(table_name, column_name, type, options)</tt>: Changes + # the column to a different type using the same parameters as add_column. + # * <tt>change_column_default(table_name, column_name, default)</tt>: Sets a + # default value for +column_name+ definded by +default+ on +table_name+. + # * <tt>change_column_null(table_name, column_name, null, default = nil)</tt>: + # Sets or removes a +NOT NULL+ constraint on +column_name+. The +null+ flag + # indicates whether the value can be +NULL+. See + # ActiveRecord::ConnectionAdapters::SchemaStatements#change_column_null for + # details. + # * <tt>change_table(name, options)</tt>: Allows to make column alterations to + # the table called +name+. It makes the table object available to a block that + # can then add/remove columns, indexes or foreign keys to it. + # * <tt>rename_column(table_name, column_name, new_column_name)</tt>: Renames + # a column but keeps the type and content. + # * <tt>rename_index(table_name, old_name, new_name)</tt>: Renames an index. + # * <tt>rename_table(old_name, new_name)</tt>: Renames the table called +old_name+ + # to +new_name+. + # + # === Deletion + # + # * <tt>drop_table(name)</tt>: Drops the table called +name+. + # * <tt>drop_join_table(table_1, table_2, options)</tt>: Drops the join table + # specified by the given arguments. + # * <tt>remove_column(table_name, column_name, type, options)</tt>: Removes the column + # named +column_name+ from the table called +table_name+. + # * <tt>remove_columns(table_name, *column_names)</tt>: Removes the given + # columns from the table definition. + # * <tt>remove_foreign_key(from_table, options_or_to_table)</tt>: Removes the + # given foreign key from the table called +table_name+. + # * <tt>remove_index(table_name, column: column_names)</tt>: Removes the index + # specified by +column_names+. # * <tt>remove_index(table_name, name: index_name)</tt>: Removes the index # specified by +index_name+. + # * <tt>remove_reference(table_name, ref_name, options)</tt>: Removes the + # reference(s) on +table_name+ specified by +ref_name+. + # * <tt>remove_timestamps(table_name, options)</tt>: Removes the timestamp + # columns (+created_at+ and +updated_at+) from the table definition. # # == Irreversible transformations # @@ -161,22 +288,15 @@ module ActiveRecord # in the <tt>db/migrate/</tt> directory where <tt>timestamp</tt> is the # UTC formatted date and time that the migration was generated. # - # You may then edit the <tt>up</tt> and <tt>down</tt> methods of - # MyNewMigration. - # # There is a special syntactic shortcut to generate migrations that add fields to a table. # # 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 up + # def change # add_column :tablenames, :fieldname, :string # end - # - # def down - # remove_column :tablenames, :fieldname - # end # end # # To run migrations against the currently configured database, use @@ -188,9 +308,12 @@ module ActiveRecord # # To roll the database back to a previous migration version, use # <tt>rake db:migrate VERSION=X</tt> where <tt>X</tt> is the version to which - # you wish to downgrade. If any of the migrations throw an - # <tt>ActiveRecord::IrreversibleMigration</tt> exception, that step will fail and you'll - # have some manual work to do. + # you wish to downgrade. Alternatively, you can also use the STEP option if you + # wish to rollback last few migrations. <tt>rake db:migrate STEP=2</tt> will rollback + # the latest two migrations. + # + # If any of the migrations throw an <tt>ActiveRecord::IrreversibleMigration</tt> exception, + # that step will fail and you'll have some manual work to do. # # == Database support # @@ -279,21 +402,6 @@ module ActiveRecord # The phrase "Updating salaries..." would then be printed, along with the # benchmark for the block when the block completes. # - # == About the schema_migrations table - # - # Rails versions 2.0 and prior used to create a table called - # <tt>schema_info</tt> when using migrations. This table contained the - # version of the schema as of the last applied migration. - # - # Starting with Rails 2.1, the <tt>schema_info</tt> table is - # (automatically) replaced by the <tt>schema_migrations</tt> table, which - # contains the version numbers of all the migrations applied. - # - # As a result, it is now possible to add migration files that are numbered - # lower than the current schema version: when migrating up, those - # never-applied "interleaved" migrations will be automatically applied, and - # when migrating down, never-applied "interleaved" migrations will be skipped. - # # == Timestamped Migrations # # By default, Rails generates migrations that look like: @@ -311,9 +419,8 @@ module ActiveRecord # # == Reversible Migrations # - # Starting with Rails 3.1, you will be able to define reversible migrations. # Reversible migrations are migrations that know how to go +down+ for you. - # You simply supply the +up+ logic, and the Migration system will figure out + # You simply supply the +up+ logic, and the Migration system figures out # how to execute the down commands for you. # # To define a reversible migration, define the +change+ method in your @@ -393,13 +500,21 @@ 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 def load_schema_if_pending! - if ActiveRecord::Migrator.needs_migration? - ActiveRecord::Tasks::DatabaseTasks.load_schema + if ActiveRecord::Migrator.needs_migration? || !ActiveRecord::Migrator.any_migrations? + # Roundtrip to Rake to allow plugins to hook into database initialization. + FileUtils.cd Rails.root do + current_config = Base.connection_config + Base.clear_all_connections! + system("bin/rake db:test:prepare") + # Establish a new connection, the old database may be gone (db:test:prepare uses purge) + Base.establish_connection(current_config) + end check_pending! end end @@ -418,7 +533,10 @@ 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 @@ -465,7 +583,7 @@ 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 @@ -481,13 +599,13 @@ 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| @@ -498,7 +616,7 @@ module ActiveRecord end def reverting? - @connection.respond_to?(:reverting) && @connection.reverting + connection.respond_to?(:reverting) && connection.reverting end class ReversibleBlockHelper < Struct.new(:reverting) # :nodoc: @@ -555,7 +673,7 @@ 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 @@ -644,13 +762,14 @@ module ActiveRecord end def method_missing(method, *arguments, &block) - arg_list = arguments.map{ |a| a.inspect } * ', ' + 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) + if [:rename_table, :add_foreign_key].include?(method) || + (method == :remove_foreign_key && !arguments.second.is_a?(Hash)) arguments[1] = proper_table_name(arguments.second, table_name_options) end end @@ -725,7 +844,9 @@ 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 @@ -817,7 +938,7 @@ 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? @@ -836,25 +957,24 @@ module ActiveRecord SchemaMigration.table_name end - def get_all_versions - SchemaMigration.all.map { |x| x.version.to_i }.sort + def get_all_versions(connection = Base.connection) + if connection.table_exists?(schema_migrations_table_name) + SchemaMigration.all.map { |x| x.version.to_i }.sort + else + [] + end end def current_version(connection = Base.connection) - sm_table = schema_migrations_table_name - if connection.table_exists?(sm_table) - get_all_versions.max || 0 - else - 0 - end + get_all_versions(connection).max || 0 end def needs_migration?(connection = Base.connection) - current_version(connection) < last_version + (migrations(migrations_paths).collect(&:version) - get_all_versions(connection)).size > 0 end - def last_version - last_migration.version + def any_migrations? + migrations(migrations_paths).any? end def last_migration #:nodoc: @@ -863,14 +983,10 @@ module ActiveRecord def migrations_paths @migrations_paths ||= ['db/migrate'] - # just to not break things if someone uses: migration_path = some_string + # just to not break things if someone uses: migrations_path = some_string Array(@migrations_paths) end - def migrations_path - migrations_paths.first - end - def migrations(paths) paths = Array(paths) |