Question

I have the following models, with their relevant associations:

class User < ActiveRecord::Base
  has_many :reviews
  has_many :ratings
end

class Product < ActiveRecord::Base
  has_many :reviews
  has_many :ratings
end

class Review < ActiveRecord::Base
  belongs_to :product
  belongs_to :user
end

class Rating < ActiveRecord::Base
  belongs_to :product
  belongs_to :user
end

Given a specific Rating, I need to get to the corresponding Review (if a review exists).

I need to keep ratings and reviews loosely coupled. (I do not want to set up my model so that a Review belongs_to a Rating)

How should I set up a rating's association to reviews?

Once I’m working with a specific rating in a view, I can call @rating.product.reviews.where(:user_id => @rating.user.id).first, but I’d like it to be cleaner/more efficient if possible.

Any ideas?

Thanks.

Answer 1

Try using :conditions like so:

class Rating < ActiveRecord::Base
  has_many :reviews,
           :through => :user,
           :source => :reviews,
           :conditions => ['#{Review.table_name}.product_id = #{product_id}']
end

If that doesn’t work, do this instead (very much like what @RobinBrouwer answer):

class Rating < ActiveRecord::Base
  def reviews
    user.reviews.where(:product => product)
  end
end