referencing belongs_to association of a belongs_to association

Question

I have the following relationships that work in the rails console but not when I run the site what I am doing wrong?

class C < ActiveRecord::Base
  belongs_to :b
end

class B < ActiveRecord::Base
  belongs_to :a
  has_many :c

  def title
    a.title
  end
end

Table C has a foreign key to B and B has a foreign key to A.

This works in the rails console.

c = C.find(12)
c.b.title

But it doesn't work when I run the site.

Here is the error I get

NoMethodError (undefined method `title' for #<ActiveRecord::Associations::BelongsToAssociation:0x104feb5a0>):

Answer 1

I had to turn the class B title method into a class method to get it to work.

Answer 2

Rather than defining a method to do this, delegate! In app/models/c.rb:

delegate :title, :to => :b

And then in app/models/b.rb:

delegate :title, :to => :a

Answer 3

has_one(association_id, options = {}) Specifies a one-to-one association with another class. This method should only be used if the other class contains the foreign key. If the current class contains the foreign key, then you should use belongs_to instead. See also ActiveRecord::Associations::ClassMethods’s overview on when to use has_one and when to use belongs_to.