my $dumper = Data::Dumper->new();
  $dumper->Terse(1);
  $dumper->Indent(0);

  my $sth = $dbh->prepare( 'SELECT * FROM table' );
  $sth->execute();

  # open a file to track all ids
  my $id_file_name = 'all-ids.txt';
  open my $id_fh, "> $id_file_name"
    or die "opening $id_file_name: $!"

  # array position of primary key
  my $id_ix = 0; 

  while ( my $cur = $sth->fetch() )
  {
      my $id = $cur->[$id_ix];
      open my $fh, "> $id"
        or { do warn "opening $id: $!"; next };
      print $fh $dumper->($cur);
      close $fh or warn "closing $id: $!";
      print $id_fh "$id\n";
  }

  close $id_fh
    or die "closing $id_file_name: $!";

  $sth->finish();

##</code><code>##

  # open a file to track all ids
  my $id_file_name = 'all-ids.txt';
  open my $id_fh, $id_file_name
    or die "opening $id_file_name: $!"
  my @ids = map { s/\s+$//; $_ } <$id_fh>;
  close $id_fh or die "closing $id_file_name: $!";

  my $n_cols = XXX; # how many columns in "table"?
  my $places = join ',', ('?') x $n_cols;
  my $ins = $dbh->prepare( "INSERT INTO table" .
                           "  VALUES ( $places )" );
  
  local $/ = undef;
  foreach my $id ( @ids )
  {
      open my $fh, $id
        or do { warn "opening $id: $!"; next };
      my $str = <$fh>;
      close $fh
        or do { warn "closing $id: $!"; next };

      my $aref = eval $str;
      if ( !$aref || $@ )
      {
          warn "$id: eval failed (str='$str')";
          next;
      }

      $ins->execute( @$aref );
  }

##</code><code>##

  my $subdir = sprintf '%03d', $id % 1000;
  unless ( -d $subdir ) { mkdir $subdir, 0777; }
  my $file = "$subdir/$id";