CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3ruby-on-rails-3.1
Yogzzz
Yogzzz

Reputation: 2795

Relationships between models in Rails Single Table Inheritance

I've been playing around with STI in rails and had a question about associating records with a specific model.

Say I have a Product model with the following schema:

#  id         :integer          not null, primary key
#  url_name   :string(255)      not null
#  cover_img  :string(255)
#  created_at :datetime         not null
#  updated_at :datetime         not null

From this Product model, I create 2 inherited models:

Foo:

class Foo < Product

end

Bar:

class Bar < Product

end

Say I save a record to Foo(A), and a record to Bar(B). When I call Product.all, I expect to get all records A and B. However when i call Foo.all or Bar.all I expect to only retrieve A and B respectively, but what happening is that when I call either Foo.all or Bar.all, I get the result I get when call Product.all. How to I configure this relationship to get the expected results?

I am using rails 3.2.6 and Ruby 1.9.3

Upvotes: 0

Views: 340

Answers (2)

ajselvig
ajselvig

Reputation: 718

You need to add a 'type' column to your products table so that ActiveRecord can distinguish between instances of the different types. This column should have a string type, like:

create_table :products do |t|
  # your other columns
  t.string :type
end

Upvotes: 2

Trip
Trip

Reputation: 27124

The answer lies in how you are saving the object. You're probably saving them as either a Foo or a Bar, and not as a Product as you should be. When I use inherited models like you are, I'm generally only doing so to inherit communal ways to identify their datas.

So I would have for example, a Question, and two different types of questions like a Grammar and a Visual that would both inherit Question. But I would be saving the Object as question in the QuestionsController.

Just like you should be saving your objects with the ProductsController.

Upvotes: 0

Related Questions