public function wrap($criteria) {
        if ($criteria instanceof xPDOQuery) {
            $this->_class= $criteria->_class;
            $this->_alias= $criteria->_alias;
            $this->graph= $criteria->graph;
            $this->query= $criteria->query;
        }
        $this->sql= $criteria->sql;
        $this->stmt= $criteria->stmt;
        $this->bindings= $criteria->bindings;
        $this->cacheFlag= $criteria->cacheFlag;
    }