my @db_colnames = ('lastname','firstname','middlename');

my @rows = $schema->resultset( 'myTable' )->search({},
                                                      {order_by => [qw/ lastname firstname middlename /] }
);

foreach my $row (@rows) {
    foreach my $col (@db_colnames) {
       print $row->$col ."\t";
    }
    print "\n";
}