Rails的：has_many通过

Question

I am having issues setting up model relations in Rails.

I have a User. A user can have many requests. A request can have one response. I set up my models like this:

Class User < ActiveRecord::Base
    has_many :user_requests
    has_many :request_responses, through: :user_requests
end

Class UserRequest < ActiveRecord::Base
    belongs_to :user
    has_one :request_response
end

Class RequestResponse < ActiveRecord::Base
    belongs_to :user_request
end

Whenever I try to do something like:

UserRequest.request_response.id

I get errors that say either the relationship doesn't exist or the column does not exist in the table. Have I set up my relationships incorrectly?

Answer 1

You will get error:

UserRequest.request_response.id

Because:

1. request_response is expected to be a class method of UserRequest .
2. Association is defined as request_responses , not request_response , so calling user. request_response user. request_response won't work either.

What to do?

call user.request_response_ids where user = User.first .