Explanation/Reference:
This is a known issue, hibernate does not perform cascade delete via HQL. If you load the object and delete it using session.delete(object); then the cascade relations are respected. Not via HQL. You have either of the 3 options.
* Load them and call session.delete();
* Load all the child items via HQL, delete them, and then the real objects.
* Put a cascade link at the database level. So when you delete it, the DB will take care of it.
Reference: hibernate doesn't remove child with named query, but removes with session.delete()
http://stackoverflow.com/questions/4275291/hibernate-doesnt-remove-child-with-named-query-but- removes-with-session-delete