$db_name='dbname';
$db_user='user';
$db_password='password';
// connessione al DATABASE
$db_conn = mysql_connect("localhost",$db_user,$db_password);
if (!$db_conn)
{
echo "ERRORE !! non riesco a collegarmi al database!";
exit();
}
//Now the update
$update="update table_name set field=$field where id=$id";
$db_query_programmi=mysql_db_query($db_name,$update);
$field is passed from the previous form page
If you write in the update ....."where id=$id" you update only element $id where $id is passed from the previous web page.