sub handler {
   my $r = Apache2::Request->new(shift);
   my %in_cookies = Apache2::Cookie->fetch ($r);
   my $session = $in_cookies{"ID"} && $in_cookies{"ID"}->value;
   
   my $dbh = DBI->connect('DBI:mysql:mydb', 'myuser', 'mypasswd', { RaiseError => 1, AutoCommit => 1, PrintError => 1} ) or die $DBI::errstr;
   my $shipaddr1 = $r->param("shipaddr1");
   my $shipaddr2 = $r->param("shipaddr2");
   my %ship_address = (addr1 => $shipaddr1, addr2 => $shipaddr2);
   unless ($dbh->selectrow_array("select count(*) from bill where session=?",undef,$session)){ # new entry
      $dbh->do("insert into bill (session) values(?)",undef,$session);
      while ( my ($key,$value) = each %ship_address ) {
         $dbh->do("update bill set ship$key = ? where session = ?", undef, $value, $session);
      }
   }