rails, how to alias a relation in model?

Question

I need to override the name of a relation, here is my model:

class User < ActiveRecord::Base

  has_many :class_rooms_member_ships

  has_many :class_rooms
  has_many :class_rooms, :through=> :class_rooms_member_ships

end

now, I need another name to use when I want to get class_rooms :through=> :class_rooms_member_ships

how can I achieve this:

user.class_rooms
user.class_rooms_through

Any idea ?

Have you checked http://stackoverflow.com/questions/1163032/rails-has-many-with-alias-name? — zsquare, May 31 '12 at 04:50
but, my case is a little bit different, I am using has_many through — simo, May 31 '12 at 10:11
The question's title is misleading in a way. Strictly speaking you are not asking for an alias as stated in the question. Because that would mean that the association would still have to be accessible by its original name. Instead you are asking for a way to define the name of the association. The answer for the question in the title is probably `alias_attribute`. — Andreas Baumgart, Jul 15 '17 at 16:46

score 14 · Accepted Answer · answered May 31 '12 at 10:19

14

has_many :classrooms_though_memberships, :through=> :class_rooms_member_ships, 
                                     :class_name => 'ClassRoom', 
                                     :foreign_key => 'class_room_id',
                                     :source => :class_room

This should work.

answered May 31 '12 at 10:19

Seb Jacobs

156
3

exactly, it worked fine, it seems that the source was missing, thanks – simo May 31 '12 at 18:49
1

`class_name` and `foreign_key` should not be necessary, `source` specifies the relation name. – Johannes Jasper Apr 19 '16 at 17:34

score 0 · Answer 2 · answered May 31 '12 at 05:11

0

Something like this should work:

has_many :classrooms_though_memberships, :through=> :class_rooms_member_ships, 
                                         :class_name => 'ClassRoom', 
                                         :foreign_key => 'class_room_id'

answered May 31 '12 at 05:11

Chris Mohr

3,639
1
13
9

I tried it, but, I've got this error: ActiveRecord::HasManyThroughSourceAssociationNotFoundError in ClassRoomsMemberShipsController#index Could not find the source association(s) :classrooms_though_membership or :classrooms_though_memberships in model ClassRoomsMemberShip. Try 'has_many :classrooms_though_memberships, :through => :class_rooms_member_ships, :source => '. Is it one of ? – simo May 31 '12 at 09:13

rails, how to alias a relation in model?

2 Answers2