I have the following entities:
- User
- Company
- Organization
Users need to be able to add Users, Companies, Organizations, and future party objects to their friend list.
My original idea involved using a Friendship object with a polymorphic relationship to the friend like so:
Simplified Friendship schema:
- user_id
- friendable_id
- friendable_type
User - has_many :businesses, :through => :friendships, :conditions => ['friendable_type=?', 'Business'], :source => :friendable
My problem is that Ruby on Rails ActiveRecord does not support has_many through relationships through polymorphic relationships on the join table such.
In the end I want to have a single join table to be able to iterate through to get a list of friends of all types, certain types, etc. like below:
john = User.find(5)
john.friendships.map {|friendship| friendship.friendable }
john.businesses (has_many :through scoped to only the businesses)
john.organizations (has_many :through scoped only to the organizations)
I've considered making the User, Business, and Organization inherit from a generic Party class and making the association point to the base Party class, but in the context of an ORM that leads to a bunch of junk fields and it just seems dirty.
What I'd like to know is how others would approach a situation like this where you want to create one-to-many relationships to similar objects through a common join table using ActiveRecord while avoiding this error: :)
Cannot have a has_many :through association 'User#businesses' on the polymorphic object 'Friendship#friendable'.
Any advice greatly appreciated.
Thanks!