如何进行多个has_one模型关联？

Question

I'm trying to access the title of a user's role in a view. I want to be able to do this user.user_details.role.title .

user.user_details.role gives me the error undefined method role' for #`

What's wrong with my associations that this is not working?

class User < ActiveRecord::Base
  has_one :user_details, :dependent => :destroy
  has_one :role, :through => :user_details
end

class UserDetails < ActiveRecord::Base
  belongs_to :user
  has_one :role
end

class Role < ActiveRecord::Base
  belongs_to :user_details
end

Answer 1

Your naming for UserDetails model is wrong. Change it to UserDetail & also update in the association.

Then you will be able to access the role by user.user_detail.role . Because for has_one association you have to use singular names.

class User < ActiveRecord::Base
  has_one :user_detail, :dependent => :destroy
  has_one :role, :through => :user_detail
end

class UserDetail < ActiveRecord::Base
  belongs_to :user
  has_one :role
end

class Role < ActiveRecord::Base
  belongs_to :user_detail
end