mirror of https://github.com/rails/rails
fixing documentation, removing unused AS files
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@ -1,6 +1,3 @@
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require 'active_support/core_ext/kernel/singleton_class'
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require 'active_support/core_ext/module/aliasing'
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module ActiveRecord
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# Exception that can be raised to stop migrations from going backwards.
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class IrreversibleMigration < ActiveRecordError
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@ -43,11 +40,11 @@ module ActiveRecord
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# Example of a simple migration:
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#
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# class AddSsl < ActiveRecord::Migration
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# def self.up
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# def up
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# add_column :accounts, :ssl_enabled, :boolean, :default => 1
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# end
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#
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# def self.down
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# def down
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# remove_column :accounts, :ssl_enabled
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# end
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# end
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@ -63,7 +60,7 @@ module ActiveRecord
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# Example of a more complex migration that also needs to initialize data:
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#
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# class AddSystemSettings < ActiveRecord::Migration
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# def self.up
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# def up
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# create_table :system_settings do |t|
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# t.string :name
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# t.string :label
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@ -77,7 +74,7 @@ module ActiveRecord
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# :value => 1
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# end
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#
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# def self.down
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# def down
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# drop_table :system_settings
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# end
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# end
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@ -147,11 +144,11 @@ module ActiveRecord
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#
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# This will generate the file <tt>timestamp_add_fieldname_to_tablename</tt>, which will look like this:
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# class AddFieldnameToTablename < ActiveRecord::Migration
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# def self.up
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# def up
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# add_column :tablenames, :fieldname, :string
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# end
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#
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# def self.down
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# def down
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# remove_column :tablenames, :fieldname
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# end
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# end
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@ -179,11 +176,11 @@ module ActiveRecord
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# Not all migrations change the schema. Some just fix the data:
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#
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# class RemoveEmptyTags < ActiveRecord::Migration
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# def self.up
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# def up
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# Tag.find(:all).each { |tag| tag.destroy if tag.pages.empty? }
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# end
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#
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# def self.down
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# def down
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# # not much we can do to restore deleted data
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# raise ActiveRecord::IrreversibleMigration, "Can't recover the deleted tags"
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# end
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@ -192,12 +189,12 @@ module ActiveRecord
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# Others remove columns when they migrate up instead of down:
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#
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# class RemoveUnnecessaryItemAttributes < ActiveRecord::Migration
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# def self.up
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# def up
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# remove_column :items, :incomplete_items_count
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# remove_column :items, :completed_items_count
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# end
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#
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# def self.down
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# def down
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# add_column :items, :incomplete_items_count
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# add_column :items, :completed_items_count
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# end
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@ -206,11 +203,11 @@ module ActiveRecord
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# And sometimes you need to do something in SQL not abstracted directly by migrations:
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#
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# class MakeJoinUnique < ActiveRecord::Migration
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# def self.up
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# def up
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# execute "ALTER TABLE `pages_linked_pages` ADD UNIQUE `page_id_linked_page_id` (`page_id`,`linked_page_id`)"
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# end
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#
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# def self.down
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# def down
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# execute "ALTER TABLE `pages_linked_pages` DROP INDEX `page_id_linked_page_id`"
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# end
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# end
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