CODEWITHSUNDEEP
ruby-on-rails
Spyros
Spyros

Reputation: 48706

Rails Polymorphic Associations : How to get and change commentable?

There are 3 models, say Article, Picture and Comment. Comment is the polymorphic model, of course.

Now, i can do something like @article.comments and grab the comments, but if i have a comment, how can i know if it originates from an article or picture ? The db only holds an id. I tried that (http://guides.rubyonrails.org/association_basics.html#polymorphic-associations), but just got back nil on commentable.

Moreover, how can i move a picture comment to an article comment ? The comment is bound with a particular article id on commentable_id, how can i change that particular comment to becoming a comment for a specific picture ?

EDIT: I TRIED THAT AND DID NOT WORK 

ruby-1.9.2-p180 :001 > user = User.find_by_username('name')
ruby-1.9.2-p180 :002 > user.owned_items
 => [#<OwnedItem id: 81233384, ownable_id: 861022540, user_id: 986759322, ...
ruby-1.9.2-p180 :003 > user.owned_items[0].ownable
 => nil

Upvotes: 0

Views: 245

Answers (1)

Ivan
Ivan

Reputation: 882

def Article < ActiveRecord::Base
  has_many :comments, :as => :commentable
end

def Picture < ActiveRecord::Base
  has_many :comments, :as => :commentable
end

def Comment < ActiveRecord::Base
  belongs_to :commentable, :polymorpic => true
end

But you probably was already so far ;) Now you can do something like comment.where(:commentable_type => 'Event').commentable and it will return Event for a comment.

Upvotes: 1

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