Hello,

I've just started using Hibernate and have come across a small problem. I have a class RouteSet, which contains a Set of class Route (defined as a one-to-many relationship).

When my app starts, I retrieve my RouteSet object from the database. My problem is this: If I then reassign the underlying set reference using RouteSet.setRoute(Set<Route> newRoutes) and persist the object, any Route objects no longer in the Set are not deleted from the database; instead their foreign key is set to null.

I thought that setting cascade="all-delete-orphan" on RouteSet would fix this problem, but it doesn't appear to. Does anyone have any ideas?

Regards,
Adam.

Extract from RouteSet.hbm.xml:

Hi,

Use this:

RouteSet.getRoute().clear();
RouteSet.getRoute().addAll(your new set);

If it doesn't work, post more details (mappings for RouteSet and Route).

Hi Tom,

I'm afraid doing a clear() followed by addAll() failed to solve the problem. However, I realise I'd fallen into a common newbie trap to do with parent/child relationships, discussed here:

http://www.hibernate.org/hib_docs/v3/re ... child.html

So it looks like the most elegant way of resolving this is to model it as a bi-directional association. I'll probably go ahead and do this, but does anyone have any alternatives? It seems quite heavyweight generating so many tables given the relatively simple object model I'm dealing with.

Thanks,
Adam.

Hi,

Even if you make it bi-directional, you will still have to use the code from the previous post.

Another is option is to manage the relation by hand (issue select, insert, update, delete statements). Not recommanded in my opinion.