On my site everything can be commented (videos, articles, posts, other comments, whatever), 14 different models. All comments are governed by Comment model. The question is: how do I specify association between Comment and all other models? Adding 14 foreign keys is definitely not an option, same as bunch of intermediary tables. Also please note that I don’t want to make a virtual relation (make get/setComments methods for each model or through behavior with own code that’ll load/save comments).