protected function mapID($id) {
        $idArray = (array)$id;

        $result = [];
        foreach ($this->getPrimaryKey() as $i => $column) {
            if (isset($idArray[$i])) {
                $result[$column] = $idArray[$i];
            } elseif (isset($idArray[$column])) {
                $result[$column] = $idArray[$column];
            } else {
                $result[$column] = null;
            }
        }

        return $result;
    }