Folks Can a model just have a belongs_to only? or do you have to have a belongs_to and a has_many or has_one on the other model?
Of course you can.
What belongs_to and their counterparts does is create a method to access an existing relationship, the actual relationship is made in the tables themselves by adding model_id columns, for instance:
class User < ActiveRecord::Base
has_one :address
end
class Address < ActiveRecord::Base
belongs_to :user
end
Shows the address whose addresses.user_id = users.id
User.last.address
Shows the user whose users.id = addresses.user_id
Address.last.user
If you don’t need to access the relationship in the Address model just delete belongs_to :user:
class Address < ActiveRecord::Base
end
User.last.address # Shows address
Address.last.user # NoMethodError: undefined method `user’
