Is it possible to move an entity from one collection to another?

I have two top level entities A and B which both have one-to-many references to another entity C, which happens to have its own network of stuff below it.

Cascade deletes are working fine - if I delete C, it and everything below it goes away. Also, if I delete A or B, then it and its children also go away. So far so good, and I want to keep this cascading behavior.

Now the interesting part.

I want to take C, remove it from A's one-to-many collection and add it to B's one-to-many collection, preserving the object network under C.

a.getChildren().remove( c );
c.setParent(null);
b.getChildren().add(c);
c.setParent( b );

I get errors like "Found two representations of same collection" the moment I do the add().




I'd think this would be a trivial reassignment of some foreign keys, but there seems to be more to the story that I'm missing.

Does Hibernate assume remove() is a delete? The object c is not being orphaned.

Thanks,
-Walt Stoneburner | Hibernate 3.2.5 / Hibernate Annotations 3.3.0.GA

Do you use 'delete-orphan' in cascade attribute of these collections? If so, Hibernate will issue 'delete' to object once it has been removed from this collection. No matter if you assign another parent to it.

There has already been a topic about it on this forum, I will give link if I find it. I quote from memory: "delete-orphan is a feature that sometimes may help. If it doesn't work with your problem - don't use it".

My hope was that I could get away with the delete-orphan in the even the parent object was deleted.

Sounds like, since I need object C to hang around after removal, that I need to manage both ends of the delete. Not a problem, just needed to know that was the case.

Slightly related, do you know of the XML is "all, delete-orphan" as shown by the documentation, or if it's "all-delete-orphan" as, unfortunately, also shown by the documentation?

Thank you!

I think there is no difference, look at this post:
http://forum.hibernate.org/viewtopic.php?t=938758

I do exactly have the same issue [moving entities between collection] explained using diagram by Newbie. Can someone give the solution/advise to resolve this issue