public function select_one($table, $field = null, array $where = [], array $order = [], int $start = 0)
  {
    if ( $r = $this->_exec(...$this->_add_kind($this->_set_limit_1(\func_get_args()))) ){
      if ( \is_object($r) ){
        return ($a = $r->get_irow()) ? $a[0] : false;
      }
      $this->log('ERROR IN RSELECT_ONE', $r);
    }
    return false;
  }