STI and polymorphs

Question

I have problem with my code

class Post < ActiveRecord::Base
end

class NewsArticle < Post
  has_many :comments, :as => :commentable, :dependent =>         


        

Answer 1

Good question. I had exactly the same problem using Rails 3.1. Looks the problem is not solved yet. Apparently, using polymorphic associations in combination with Single Table Inheritance (STI) in Rails is a bit complicated.

The current Rails documentation for Rails 3.2 gives this advice for combining polymorphic associations and STI:

Using polymorphic associations in combination with single table inheritance (STI) is a little tricky. In order for the associations to work as expected, ensure that you store the base model for the STI models in the type column of the polymorphic association.

In your case the base model would be "Post", i.e. "commentable_type" should be "Post" for all comments.