Question

I have a model named feedback with attributes, rating and review. A product may have a feedback, a appointment may have a feedback, a user may have a feedback.

I could add individual fields, like user_id, product_id, appointment_id in the feedbacks table, but that does not seem to be a very good scalable solution. The other option in my mind is to use a generalized, reference_id field, and a reference_model field which can be populated with the model name converted to string, and then I could manually interpret if the id entered in reference_id belongs to a user, product or an appointment.

What would be the best way of going about associating each feedback with any one of the 3 models, at a given time?

Answer 1

You should read about Polymorphic Associations.

class Picture < ActiveRecord::Base
  belongs_to :imageable, :polymorphic => true
end

class Employee < ActiveRecord::Base
  has_many :pictures, :as => :imageable
end

class Product < ActiveRecord::Base
  has_many :pictures, :as => :imageable
end

There’s even a nice RailsCast.