// delete the record in the database in a separate transaction using
// native SQL so that the in-memory instance is not altered
em.getTransaction().begin();
String sql = "DELETE FROM L2_PObject WHERE id="+oid;
em.createNativeQuery(sql).executeUpdate();
em.getTransaction().commit();
// the object cache does not know that the record was deleted
assertTrue(em.contains(pc));
// nor does the data cache