my $sql;
foreach my $table (sort keys %$config) {
  my $sql = qq{ insert into $table ( id, balance ) values ( ?, ? ) };
  my $sth = $dbh->prepare( $sql );
    
  while (my ($col, $val) = each %{$config->{$table}}) {
    $sth->execute( $col, $val );
  }
}