Question

I have two models:

• User
• MentoringRelationship

MentoringRelationship is a join model that has a mentor_id column and a mentee_id column (both of these reference user_ids from the users table).

How can I specify a relation called ‘mentees’ on the User class that will return all of the users mentored by this user, using the MentoringRelationships join table? What relations do we need to declare in the User model and in the MentoringRelationship model?

Answer 1

Thanks to http://blog.hasmanythrough.com/2007/10/30/self-referential-has-many-through, I was able to put something together that works.

in app/models/user.rb

  has_many :mentee_relationships, :class_name => 'MentoringRelationship', :foreign_key => :mentor_id
  has_many :mentees, :through => :mentee_relationships, :source => :mentee, :foreign_key => :mentor_id

  has_many :mentor_relationships, :class_name => 'MentoringRelationship', :foreign_key => :mentee_id
  has_one :mentor, :through => :mentor_relationships, :source => :mentor, :foreign_key => :mentee_id

in app/models/mentoring_relationship.rb

  belongs_to :mentee, :class_name => "User"
  belongs_to :mentor, :class_name => "User"