Ticket #9775: foreign_key_on_migrations_with_polymorphic_and_docs.patch

activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb

@@ -350 +350 @@
-      #
-      # There's a short-hand method for each of the type values declared at the top. And then there's 
-      # TableDefinition#timestamps that'll add created_at and updated_at as datetimes.
+      #
+      # TableDefinition#foreign_key will add an appropriately-named _id column, plus a corresponding _type
+      # column if the :polymorphic option is supplied. If :polymorphic is a hash of options, these will be
+      # used when creating the _type column. So what can be written like this:
+      #
+      #   create_table :taggings do |t|
+      #     t.integer :tag_id, :tagger_id, :taggable_id
+      #     t.string  :tagger_type
+      #     t.string  :taggable_type, :default => 'Photo'
+      #   end
+      #
+      # Can also be written as follows using foreign_key:
+      #
+      #   create_table :taggings do |t|
+      #     t.foreign_key :tag
+      #     t.foreign_key :tagger, :polymorphic => true
+      #     t.foreign_key :taggable, :polymorphic => { :default => 'Photo' }
+      #   end
-      def column(name, type, options = {})
-        column = self[name] || ColumnDefinition.new(@base, name, type)
-        column.limit = options[:limit] || native[type.to_sym][:limit] if options[:limit] or native[type.to_sym]
@@ -376 +394 @@
-        column(:created_at, :datetime)
-        column(:updated_at, :datetime)
-      end
+      
+      def foreign_key(*args)
+        options = args.extract_options!
+        polymorphic = options.delete(:polymorphic)
+        args.each do |col| 
+          column("#{col}_id", :integer, options)
+          unless polymorphic.nil?
+            column("#{col}_type", :string, polymorphic.is_a?(Hash) ? polymorphic : {})
+          end
+        end 
+      end
+      alias :fkey :foreign_key
-
-      # Returns a String whose contents are the column definitions
-      # concatenated together.  This string can then be pre and appended to