ActiveRecord: Do I need both belongs_to and has_one
activerecord, ruby-on-rails
Solution
You define the association wherever you will need it. If at some point you need to say `user.userprofile`, then include `has_one :userprofile` in `User`. Likewise, if you need to say `userprofile.user`, then include `belongs_to user` in `Userprofile`.
In other words, associations are relative. You can specify that model A `has_one :b` without specifying that model B `belongs_to :a`. You simply define what you need. The same goes for one-to-many and many-to-many associations.
Just be sure to have migrated `user_id` to the "userprofiles" table.
Problem
I have 2 models, namely user and userprofile. There is a one-to-one relationship between user and userprofile. ``` class Userprofile < ActiveRecord::Base attr_accessible :fname, :lname, :iswoman, :age, :urlphoto, :user_id belongs_to: user end class User < ActiveRecord::Base attr_accessible :name, :provider, :uid has_one: userprofile end ``` I'd like to know whether I need both class to set the connection or having just either belongs_to or has_one is enough? The same is true for the other methods, such as has-many.