You can also use the methods included from ActiveRecord::Dirty on the foreign key fields; in your case, you'd have an after_save callback like this (on Person):
after_save :cleanup_addresses def cleanup_addresses Address.destroy(shipping_address_id_was) if shipping_address_id_changed? && shipping_address_id_was Address.destroy(billing_address_id_was) if billing_address_id_changed? && billing_address_id_was end Some notes on this: - if you don't have any callbacks or observers on Address, you can simplify the .destroy calls to .delete, and save instantiating some Address objects. - if your UI allows users to swap the addresses (ie, shipping_address_id is swapped with billing_address_id, without any new DB records), you'll need to have a better check in cleanup_addresses; the current code will end up deleting both addresses in that case. --Matt Jones On Jul 24, 6:33 pm, Emma <gkilo...@gmail.com> wrote: > I'm having trouble with this model: > > class Person < AR::B > belongs_to :shipping_address, :class_name => 'Address' > belongs_to :billing_address, :class_name => 'Address' > end > > class Address < AR::B > end > > The problem is that I want Address to be a Value Object (as in DDD), > and if I do this: > p = Person.create :shipping_address => Address.new(...) > > and later I change the address: > p.shipping_address = Address.new(...) > p.save > > the first address object doesn't get deleted from the DB. It becomes > an orphan. > > I can inverse the association and use a has_one but then I have to put > two foreign keys in the address table... and that could be a problem > because there are other models that have addresses. > > Another option could be to model both associations as composed_of but > then I have to put all of the address table columns on the people > table, and repeat this on the other models that have addresses too. > > How can I solve this? Any suggestions? > Thanks in advance. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to rubyonrails-talk@googlegroups.com To unsubscribe from this group, send email to rubyonrails-talk+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
