Question

I am trying to setup my rails models where I have a User and they have many addresses but one is their primary address. I want to be able to access it like so, User.first.primary_address_id and also User.first.primary_address to get the associated Address model.

Is there a “rails way” to set this up?

I know I could create a primary_address_id field for User and populate it in an AR callback. But that wouldn’t let me do something like User.first.primary_address

Or can I create associations as “User has_many Addresses” as well as “User has_one Address”?? or something along those lines?

Answer 1

I know I could create a primary_address_id field for User and populate it in an AR callback. But that wouldn’t let me do something like User.first.primary_address

This is the correct way to do it.

User.first.primary_address

would return the first user’s primary address if they had one or nil if they didn’t.

#user.rb
has_one :primary_address

#address.rb
attr_accessor :primary #this allows you to have a primary field of the address form

after_save :check_if_primary

def check_if_primary
   user.update_attribute(:primary_address, self) if primary
end