As I understand it, I cannot force Hibernate to use a xref table when modelling one-to-many relationships.

But this is something I would want to do by default.

If I have an entity, for example representing an Address, I want to relate that entity to many other entities (Client, Company, Branch, Department, Employee etc. etc.).

This means I keep having to add more and more foreign keys as the relationships are implemented. That's a pain for support, because ALTER TABLE has to be issued in the database.

Leaving aside arguments about the pros and cons of FKs versus xref, my point is I want to be able to choose, as I can in CMP (although I hate CMP for about 10 other reasons).

This is a barrier to adoption of Hibernate for us at the moment.

Can it be done (I hope I've missed something)? I could incorrectly model the relationship as many-to-many, but I don't want to do that.

Please, someone answer!

Can I do it?

This is a simple but important question for us.

It is not supported, you have to use many-to-many for this.

Do you have any plans to support it?

Although I'm not familiar with the codebase, it would seem not a radical rework to allow, and then the users can make the decision.

It was marked as "not easy" in all discussions we had about it. I also think that the relational SQL model is broken in that case. I don't think it is in the top ten of our priority list right now. Feel free to have a look at the source, we always welcome patches. We are very responsive to user requests, but this must be only the second time in 10 months someone asked for this feature.

Fair enough. I can live with that. We might look at it ourselves.

Our perspective comes from maintaining a large application over 10 years or more.

We find that extensive use of foreign keys can cause significant problems with delivery of new releases, and also make the application harder to change.

I don't agree that the relational model is necessarily broken when you use a x-ref for one-to-many. I think that's a rather bold statement :-)
Also, with regards to performance (which I know you weren't referring to) there are cases where an xref can be have significant advantages over foreign keys (and vice-versa of course).

All in all, it's a complex subject which I would prefer that users could decide.

But thanks for your responses. We'll probably start off using many-to-many and see how that pans out.

Well, you can of course ensure integrity with a unique constraint on the "one" key in the association table. I was thinking of a different issue, so forget that statement I made before.