Question

I use Mongoid and Rails 3, and I have the following single table inheritance:

class Post
  include Mongoid::Document
  field :title, type: String
  field :content, type: String
end

There is one model ‘Article’ inherited from Post:

class Article < Post
  field :source, type: String
end

I am a novice to try STI. I learned that ‘one controller’ is a good design for base and inherited models. So I have the PostsController like this

class PostsController < ApplicationController
  def index
    @type = param[:type]  # type is passed from the route.rb
    @posts = Post.where(_type: @type)

    ...

So if @type is specified as ‘Article’, @posts will only contain the ‘Article’ type of posts. This work well in the articles view: only articles will be displayed, but not other kind of posts.

However, in the posts view, it will show both posts and articles.

I don’t want articles showing in my posts view — actually, I want only posts from the base model showing in the view. Is there a way to exclude items from inherited model in the base controller?

In other words, how can I find items only from the base model?

Answer 1

I just figured out I can use the following in the controller:

@post = Post.where(_type: "Post")

Is it the right way to go?