how to specify multiple relationships between models in rails using ActiveRecord associations

Question

Say there're two models : User and Post, i want to keep track of who has read which post, and who writes which post, which user favorites which posts etc. Then i come up with the following solution:

class User < ActiveRecord::Base
  has_many :writings
  has_many :posts, :through => :writings
  has_many :readings
  has_many :posts, :through => :readings
  #..
end

class Post < ActiveRecord::Base
  has_many :writings
  has_many :posts, :through => :writings
  #...
end

and setting up the intermediate models - Writing, Reading. this works, but finally i find out that when i writing this

@user.posts #...

the returned array contains housekeeping information both for writings and readings. How can i solve this problem.

Answer 1

You want something like this:

class User < ActiveRecord::Base
  has_many :writings
  has_many :posts, :through => :writings
  has_many :readings
  has_many :read_posts, :through => :readings, :class_name => "Post"
  #..
end

By giving the association name something other than just :posts you can refer to each one individually. Now...

@user.posts # =>  posts that a user has written via writings
@user.read_posts # => posts that a user has read via readings