function set($parm, $value = null)
    {
        if(is_array($parm)){
            foreach($parm as $k=>$v){ $this->__columns[$k] = $v; }
            return $this;
        }
        elseif(isset($this->__columns[$parm])) {
            $this->__columns[$parm] = $value;
            return $this;
        }
        else return false;
    }