foreach my $tablename (@tables) {

        my $sth = $dbh->prepare(qq{select * from $tablename limit 1}); 
        $sth->execute();
        my @fields = @{$sth->{NAME}};
        for (0 .. $#fields)
        {       
          $default_column{$fields[$_]} = $sth->{mysql_is_num}[
$_] ? 0 : '""';
        }
        $table_columns{$tablename} = \@fields; 

}