Providing support for :inverse_of as an option to associations.

You can now add an :inverse_of option to has_one, has_many and belongs_to associations.  This is best described with an example:

class Man < ActiveRecord::Base
  has_one :face, :inverse_of => :man
end

class Face < ActiveRecord::Base
  belongs_to :man, :inverse_of => :face
end

m = Man.first
f = m.face

Without :inverse_of m and f.man would be different instances of the same object (f.man being pulled from the database again).  With these new :inverse_of options m and f.man are the same in memory instance.

Currently :inverse_of supports has_one and has_many (but not the :through variants) associations.  It also supplies inverse support for belongs_to associations where the inverse is a has_one and it's not a polymorphic.

Signed-off-by: Murray Steele <muz@h-lame.com>
Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

1 files changed, 20 insertions, 0 deletions

diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 6918a4fcab..3b0e17c867 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -468,6 +468,26 @@ ActiveRecord::Schema.define do
     end
   end
 
+  # NOTE - the following 4 tables are used by models that have :inverse_of options on the associations
+  create_table :men, :force => true do |t|
+    t.string  :name
+  end
+
+  create_table :faces, :force => true do |t|
+    t.string  :description
+    t.integer :man_id
+  end
+
+  create_table :interests, :force => true do |t|
+    t.string :topic
+    t.integer :man_id
+    t.integer :zine_id
+  end
+
+  create_table :zines, :force => true do |t|
+    t.string :title
+  end
+
   except 'SQLite' do
     # fk_test_has_fk should be before fk_test_has_pk
     create_table :fk_test_has_fk, :force => true do |t|