>> I thought earlier you had written something about OrderLine belonging to two >>different kinds of order, one which was raising and one which was raised. I >>can't find it now though so I may have been someone else.
I think was talking about the class is able to have two different kinds of parents, but a class instance cannot have two parent instances. The Orderline class would have to be an IAggregatedPartof<T> for different T's but an individual orderline would only have one root. I also suspect that Greg is sorry he brought up the Customer/Order example as he has stated he knows he would have to go a different direction for a cross aggregate concern like this. He is talking about removing these concerns from within the AR boundry. My interpretation, Erik -----Original Message----- From: nhusers@googlegroups.com [mailto:nhus...@googlegroups.com] On Behalf Of Peter Morris Sent: Monday, April 27, 2009 1:13 PM To: nhusers@googlegroups.com Subject: [nhusers] Re: Version > An instance of an entity always belongs only to a single aggregate root. The problem with the official description of agg-roots is that no persistent references may be made to any of the agg-parts. This effectively means that customer/order is not an aggregate because you can reference orders independently of customers. What you need to do though is to ensure that customer is not updated by another thread because you need to do Customer.AcceptOrder(newOrder) so that you can check credit limits etc. >> Fetching strategies are meaningless if you store documents. My point was that they are specific to a RDBMS. If I use document based storage I have no need for fetch paths. << Yes that's right, but the fetch path was only part of what you gain. If you say *why* you want an order then the object which fetches the order + lines will also place a lock on the customer, ensuring it isn't modified by anyone else because it knows that the reason you need the order is to modify it and you will therefore need to ensure that the customer's credit limit isn't exceeded. It's not something I have tried yet, just something I'm thinking about since watching Udi's talk. >> Various ways most of which are mentioned here. I am really going through nhibernate right now to see if it is at all appropriate for use with DDD (this discussion will make a big impact on that decision). << Keep in mind that I haven't written an NH app yet, so far I have only read about it and have yet to get started using it. I usually use ECO from capableobjects, in which I get bi-directional associations for free. Pete --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "nhusers" group. To post to this group, send email to nhusers@googlegroups.com To unsubscribe from this group, send email to nhusers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nhusers?hl=en -~----------~----~----~----~------~----~------~--~---
