I want ActiveRecord
to lookup by a non-id column from a table.
Hope this is clear when I give you my code sample.
class CoachClass < ActiveRecord::Base
belongs_to :coach
end
class Coach < ActiveRecord::Base
has_many :coach_classes, :foreign_key => 'user_name'
end
When I do a
coach_obj.coach_classes
, this rightly triggers
SELECT * FROM `coach_classes` WHERE (`coach_classes`.user_name = 2)
(2 being the that coach's id
here which is my problem.)
I want it to trigger
SELECT * FROM `coach_classes` WHERE (`coach_classes`.user_name = 'David')
('David' being the that coach's user_name
)
user_name
is unique and present in both tables.
I do not want to have a coach_id
in my coach_classes
table for some reason.
I think you need to specify the primary key options on the associations as well:
class CoachClass < ActiveRecord::Base
belongs_to :coach, :foreign_key => 'user_name', :primary_key => 'user_name'
end
class Coach < ActiveRecord::Base
has_many :coach_classes, :foreign_key => 'user_name', :primary_key => 'user_name'
end
This specifies the method that returns the primary key of the associated object (defaulting to id
).