I've noticed that if you have only a one-to-many association between a parent and its children that when you create a new child and save it, it will first insert the new row with null in the FK. It will then flush the parent, and update that row to include the parent's PK value in the FK.

This completely breaks any attempt to do FK constraints or NULL constraints on the FK column.

If I put the many-to-one on the child and set the parent's one-to-many to inverse=true, then this works as expected. I don't want to have to make all my collections bidirectional just for this reason, especially since adding new elements is an awkward two-step process (add to collection, set parent on child).

Is there something I'm missing here? I've tried all the cascade options on the parent, is there something else I need to do to make this work as I'd expect or is this by design?

Thanks,

Aaron

Apparently this has been answered before, but I still can't find it in search. Basically, NHibernate updates collections separately from contained objects. This means that, like I feared, this is by design and the only way around it is to make the associations bidirectional. This may have been improved in H3.2, but it may never be ported... so ah well, we're stuck w/ this.

I have the same issue. Hibernate FAQ states:



Unfortunately <key not-null="true" ... /> is not supported in NHibernate as it seems. I don't know if there is a workaround.