From: David Heinemeier Hansson <david@...>
Date: 2005-02-13T00:20:08+09:00
Subject: Re: Rails question - ActiveRecord::Base#composed_of

> class Person < ActiveRecord::Base
>   composed_of :family,
>               :mapping => [%w(family_name name), %w(family_phone 
> phone),
> %w(family_address address)]
> end

This setup expects that your people table has family_name and 
family_phone as columns. The aggregation works by presenting multiple 
fields as one object, so when you do have these columns, you should be 
able to do: person.family.name and person.family.phone.

I'd say this approach is only worth it if you have considerable or very 
convenient business logic tied to your Family object, though. If it's 
just data, I'd much rather just save the trouble and do 
person.family_name.

Hint: For faster and more complete assistance, I recommend signing up 
for the Rails mailing list or visiting IRC. More information on 
http://wiki.rubyonrails.com/rails/show/HomePage
--
David Heinemeier Hansson,
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