public function addIdMethodParameter($impdata)
    {
        if ($impdata instanceof IdMethodParameter) {
            $imp = $impdata;
            $imp->setTable($this);
            if ($this->idMethodParameters === null) {
                $this->idMethodParameters = array();
            }
            $this->idMethodParameters[] = $imp;

            return $imp;
        } else {
            $imp = new IdMethodParameter();
            $imp->loadFromXML($impdata);

            return $this->addIdMethodParameter($imp); // call self w/ diff param
        }
    }