From fc7fd4c5cee277d569fd406c55fc9d147ca000c1 Mon Sep 17 00:00:00 2001 From: David Heinemeier Hansson Date: Mon, 9 Oct 2006 02:05:50 +0000 Subject: [PATCH] Docfix (closes #6040) git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@5259 5ecf4fe2-1ee6-0310-87b1-e25e094e27de --- .../lib/active_record/associations.rb | 24 +++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index 961f7cc30e..93f10c666c 100755 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -279,6 +279,30 @@ def clear_association_cache #:nodoc: # This works by using a type column in addition to a foreign key to specify the associated record. In the Asset example, you'd need # an attachable_id integer column and an attachable_type string column. # + # Using polymorphic associations in combination with single table inheritance (STI) is a little tricky. In order + # for the associations to work as expected, ensure that you store the base model for the STI models in the + # type column of the polymorphic association. To continue with the asset example above, suppose there are guest posts + # and member posts that use the posts table for STI. So there will be an additional 'type' column in the posts table. + # + # class Asset < ActiveRecord::Base + # belongs_to :attachable, :polymorphic => true + # + # def attachable_type=(sType) + # super(sType.to_s.classify.constantize.base_class.to_s) + # end + # end + # + # class Post < ActiveRecord::Base + # # because we store "Post" in attachable_type now :dependent => :destroy will work + # has_many :assets, :as => :attachable, :dependent => :destroy + # end + # + # class GuestPost < ActiveRecord::Base + # end + # + # class MemberPost < ActiveRecord::Base + # end + # # == Caching # # All of the methods are built on a simple caching principle that will keep the result of the last query around unless specifically -- GitLab