int count = s.createQuery( "update PettingZoo set address.city = null" ).executeUpdate();
assertEquals( "Incorrect discrim subclass delete count", 1, count );
count = s.createQuery( "delete Zoo where address.city is null" ).executeUpdate();
assertEquals( "Incorrect discrim subclass delete count", 1, count );
count = s.createQuery( "update Zoo set address.city = null" ).executeUpdate();
assertEquals( "Incorrect discrim subclass delete count", 1, count );
count = s.createQuery( "delete Zoo where address.city is null" ).executeUpdate();
assertEquals( "Incorrect discrim subclass delete count", 1, count );
t.commit();