Ok here’s an app as of right now.
All the app consists of are some forms for creating users, some forms for users to create comments, plus 1 additional page that displays each user and the total number of comments they have created. There is NO page that displays a comment and its user who created it.
The correct domain model based on the requirements right now is:
class User < ActiveRecord::Base has_many :comments end class Comment < ActiveRecord::Base end
This association is unidirectional, it can only be traversed in one direction.
There is no point in making this association bidirectional by adding a
belongs_to :user in
Comment. Adding that would be premature
and a case of massive over-engineering. Since the association from
User currently is not used in the app, adding it would just cause unnecessary
There is nothing wrong with unidirectional associations. Don’t make all associations bidirectional when its just not necessary; someday it might be but until then don’t do it.