public function __construct(&$xpdo, $class, $criteria = null)
 {
     parent::__construct($xpdo, $class, $criteria);
     $this->query['priority'] = '';
 }
 public function __construct(& $xpdo, $class, $criteria= null) {
     parent :: __construct($xpdo, $class, $criteria);
     $this->query['top']= 0;
 }