Question

Let’s say I have 2 tables:

Users
user_id name

Tags
tagger_id tagged_id

This describes a situation where you can

And the models that I’m trying to set up are:

class User < ActiveRecord::Base
    has_many :tags, :foreign_key => "tagger_id"
end

class Tag < ActiveRecord::Base
    belongs_to :tagger, :class => "User"
    belongs_to :tagged, :class => "User"
end

I’m trying to set it up so that when I do:

user.tags

It comes back with a list of User objects. With my current setup, it comes back with just the actual Tag record with ids instead of objects. How do I set it up so it returns a list of User objects?

I tried using:

has_many :tags, :foreign_key => "tagger_id", :source => :tagged

But it didn’t work.

Answer 1

You’re looking for has_many :through.

class User < ActiveRecord::Base
    has_many :tags, :foreign_key => "tagger_id"
    has_many :tagged, :through => :tags
end

Then user.tagged should give you the list of users you want.