Ayende @ Rahien

Nestor Rodriguez commented on NHibernate: Complex relationships

Mon, 22 Nov 2010 15:07:48 GMT

This challenge is an evidence of how NHibernate can deal with bad databases design but refactor is a must !.

Frans Bouma commented on NHibernate: Complex relationships

Sat, 20 Nov 2010 11:14:34 GMT

Paper about this subject by prof. T. Halpin: [http://www.orm.net/pdf/objectification.pdf](http://www.orm.net/pdf/objectification.pdf)

Frans Bouma commented on NHibernate: Complex relationships

Sat, 20 Nov 2010 11:08:51 GMT

I'm with Victor, this isn't elegant at all. It's also wrong: PersonAddresses is an objectified relationship (in Object Role Modeling / NIAM terms), and this means it's an entity by itself. Just because it defines a m:n relationship between person and address doesn't make it an entity which doesn't exist, and the limitation that you can't persist new addresses shows that. I fail to see why PersonAddresses has to be wiped under the rug: its name is perhaps badly chosen, but it _is_ a valid entity, that you don't want to program with it, is really ignorance: because the entity exists in the domain, you have to deal with it, and which is the reason you have to deal with it too only in 'some other fashion'. The m:n relationship between person and addresses is readonly, over the objectified relationship. I do recall having a discussion with Fabio about this some time ago on nhusers.

Scooletz commented on NHibernate: Complex relationships

Sat, 20 Nov 2010 08:51:50 GMT

Good, old-fashioned blog entry. Interesting case.

Fabio Maulo commented on NHibernate: Complex relationships

Fri, 19 Nov 2010 16:21:35 GMT

Can I refactorize that DB ? or it is untouchable ?

Corey commented on NHibernate: Complex relationships

Fri, 19 Nov 2010 14:23:46 GMT

If you really want flexibility given the table structure above and still want to handle inserts. Create a sql view that fits the exact mapping structure and let the view deal with the inserts appropriately.

Max commented on NHibernate: Complex relationships

Fri, 19 Nov 2010 13:07:58 GMT

Oops, it seems my comment is stripped. What about using idbag?

Max commented on NHibernate: Complex relationships

Fri, 19 Nov 2010 13:04:32 GMT

What about using

JasonW commented on NHibernate: Complex relationships

Fri, 19 Nov 2010 12:51:13 GMT

The tabular model and the object structure in almost all cases will be quite different, with one modelling data and the other modelling behaviour. This is something that most ORMs don't handle as elegantly as the code above.

Ayende Rahien commented on NHibernate: Complex relationships

Fri, 19 Nov 2010 12:45:05 GMT

Victor, You need to map the PersonId column on the PeopleAddresses, and then you can threat this as a standard Many To One. The scenario that was brought up was were there was another way of handling that, so I didn't bother with that

Victor Kornov commented on NHibernate: Complex relationships

Fri, 19 Nov 2010 12:25:30 GMT

Pardon my ignorance, but how "you can’t add new addresses via the Person.Addresses collection" relates to the conclusion of "this is a pretty elegant solution"? All I can think of is having another set of classes\mappings just to be able to save the person's address. That's not elegant in my books.