How to design model with two, independent and optional relations to the same model?

I've got a problem with designing my User model and making a decent form for it. I just want to ensure myself that I'm doing it wrong :) So it goes like this:

User has got two Addresses:

• a mandatory Address for identification and billing,
• an optional shipping Address that he could fill in or leave blank

I tried like this:

class User < ActiveRecord::Base
  has_one :address
  has_one :shipping_address, :class_name => 'Address', :foreign_key => 'shipping_address_id'
  accepts_nested_attributes_for :address
  accepts_nested_attributes_for :shipping_address
  #val开发者_Go百科idations for user
end

and:

class Address < ActiveRecord::Base
  #validations for address
end

And then I make a form for User using form_for and nested fields_for. Like this:

= form_for @user, :url => '...' do |a|
  = f.error_messages
  ...
    = fields_for :address, @user.build_address do |a|
      ...

But then, despite that f.error_messages generates errors for all models, fields for Addresses don't highlight when wrong.

Also I have problems with disabling validation of the second address when the user chose not to fill it in.

And I have doubts that my approach is correct. I mean the has_one relation and overall design of this contraption.

So the question:

Am I doing it wrong? How would You do that in my place?

---

What is wrong in your form is that it will build a new address every time the view is rendered, thus losing all validation errors.

In your controller, in the new action you should do something like

@user.build_address

and in your view write:

= fields_for :address, @user.address do |a|

Hope this helps.