如何在模型上引用“ user_id”，但命名为“ poster_id”和“ receiver_id”两个不同的属性？ -滑轨3

Question

This is my Feedback model:

class Feedback < ActiveRecord::Base
    belongs_to  :user
end
# == Schema Information
#
# Table name: feedbacks
#
#  id          :integer         not null, primary key
#  poster_id   :integer
#  receiver_id :integer
#  content     :string(255)
#  created_at  :datetime
#  updated_at  :datetime

This is my User model:

class User < ActiveRecord::Base
    has_many    :feedback
end
# == Schema Information
#
# Table name: users
#
#  id         :integer         not null, primary key
#  email      :string(255)
#  f_name     :string(255)
#  l_name     :string(255)
#  username   :string(255)
#  role_id    :integer
#  picture    :string(255)
#  about_me   :string(255)
#  website    :string(255)
#  created_at :datetime
#  updated_at :datetime

What I would like to do is retrieve all the feedback for a particular user. But, at my console, when I do t = User.first and then t.feedback , I get the following error:

 Feedback Load (0.2ms)  SELECT "feedbacks".* FROM "feedbacks" WHERE "feedbacks"."user_id" = 1
SQLite3::SQLException: no such column: feedbacks.user_id: SELECT "feedbacks".* FROM "feedbacks"  WHERE "feedbacks"."user_id" = 1
ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: feedbacks.user_id: SELECT "feedbacks".* FROM "feedbacks"  WHERE "feedbacks"."user_id" = 1

Now that is saying that I have no column user_id in my Feedbacks table, which makes sense - because I don't.

What I really want to happen is, I want to store the user_id of a user that posts feedback as the poster_id , and when someone receives feedback I want the user_id to be stored in the feedback object as receiver_id .

How do I do that?

Thanks.

PS Using Rails 3.1...if that has any bearing.

PPS In my User model the has_many :feedback line looks weird, because I know it should be plural. But has_many :feedbacks looks even worse :| What should I do for that too?

PPPS I looked at the foreign_key attribute of associations, but wasn't sure how to get it to work in this situation - would the association be belongs_to :poster_id, :foreign_key => user_id ? That looks weird and doesn't seem to fit the description in the api documentation of the foreign_key attribute.

Answer 1

Your associations should be defined like this:

class Feedback < ActiveRecord::Base
    belongs_to :poster, :class_name => 'User'
    belongs_to :receiver, :class_name => 'User'
end

class User < ActiveRecord::Base
    has_many :feedbacks_as_poster, :foreign_key => :poster_id, :class_name => 'Feedback'
    has_many :feedbacks_as_receiver, :foreign_key => :receiver_id, :class_name => 'Feedback'
end

If you are not sure about what the association name means or you don't like the name, you should possibly think about a little bit more about your model, maybe the naming doesn't reflect what you're trying to model with your objects.