private function _saveObjectRaw(PersistentObject $object, ClassMap $classMap, &$commands)
 {
     if ($object->isPersistent()) {
         $statement = $classMap->getUpdateSqlFor($object);
         $commands[] = $statement->update();
     } else {
         $classMap->setObjectKey($object);
         $statement = $classMap->getInsertSqlFor($object);
         $commands[] = $statement->insert();
     }
     $object->setPersistent(true);
 }