Mongoid relational Polymorphic Association

Question

Does anyone know how to do a polymorphic association in Mongoid that is of the relational favor but not the embedding one.

For instance this is my Ass

Answer 1

Rails 4+

Here's how you would implement Polymorphic Associations in Mongoid for a Comment model that can belong to both a Post and Event model.

The Comment Model:

class Comment
  include Mongoid::Document
  belongs_to :commentable, polymorphic: true

  # ...
end

Post / Event Models:

class Post
  include Mongoid::Document
  has_many :comments, as: :commentable

  # ...
end

---

Using Concerns:

In Rails 4+, you can use the Concern pattern and create a new module called commentable in app/models/concerns:

module Commentable
  extend ActiveSupport::Concern

  included do
    has_many :comments, as: :commentable
  end
end

and just include this module in your models:

class Post
  include Mongoid::Document
  include Commentable

  # ...
end