# determine the field names
  if ($colNamesHdl) {
    @ff=();
    for ($i=0; $i <= $#$colNamesHdl; $i++) {
      push(@ff, $$colNamesHdl[$i]);
    }

  } else {
    $k  = $$rowsHdl[0];
    @ff = keys(%$k);
  }