posto qui di seguito gli script ma il risultato è invariato
cnx_db.php
<?php
$db_host="localhost";
$db_db="veicoli";
$db_user="root";
$db_pw="";
$db_slc = mysql_connect($db_host,$db_user,$db_pw);//connessione al server
$db_cnx= mysql_select_db($db_db)or die (mysql_error());
?>
modify.php
<html>
<head>
<title>!!!!! M O D I F I C A !!!!!!</title>
</head>
<body>
<?php

$confirm = $_POST['confirm'];
if (isset($_GET['id'])){
$id =(int) $_GET['id'];}else{$id=0;}
if ($confirm)
{
include('cnx_db.php');
if(!$db_cnx){
echo 'Errore connessione nn riuscita'.mysql_error().'per favore riporova più tardi';
}
else{
// if(get_magic_quotes_gpc()){//evita sql injection
// $qstring = stripslashes($id);
// }
// $purchase_id=mysql_real_escape_string($id);
$query = "select * from veicoli where id='".$id."'";
$dbResult = mysql_query($query);
$AffectedRows = mysql_num_rows($dbResult);
if ($AffectedRows==0){
echo"<h3>non ci sono record con i criteri selezionati</h3>";
}
else{
mysql_data_seek($dbResult, 0);
$row = mysql_fetch_row($dbResult);
print("<table>");
print("<form method=\"post\"action=\"{$_SERVER['PHP_SELF']}\">");
foreach($row as $k=>$v)
{
$myfield= mysql_fetch_field($dbResult, $k);
print("<tr><td>$myfield->name</td>");
print("<td><input ttype=\"text\" value=\"".$v."\" name=\"". $myfield->name."\" size=\"100\" maxlength=\"100\"></td></tr>");
}
print("<tr><td colspan=\"2\"><input type=\"submit\ value=\"conferma modifiche\"></td></tr> ");
print("<input type=\"hidden\" name=\"confirm\" value=\"1\">");
print("</form>");
print("</table>");

mysql_free_result($dbResult);
mysql_close($db_slc);
}

}
}
else{
$marca=$_POST['marca'];
$modello=$_POST['modello'];
$km=$_POST['km'];
$cat=$_POST['categoria'];
$pz=$_POST['pz'];
$anno=$_POST['anno'];
$opt=$_POST['optional'];
$ft1=$_POST['ft1'];
$ft2=$_POST['ft2'];
$ft3=$_POST['ft3'];
$ft4=$_POST['ft4'];
$query="update veicoli set marca='".$marca."' where id='$id'";
// ,modello='".$modello."',km='".$km."',categoria='". $cat."',pz='".$pz."',anno='".$anno."',optional='". $opt."',ft1='".$ft1."',ft2='".$ft2."',ft3='".$ft3. "',ft4='".$ft4."' where id='$id'";
$dbResult= mysql_query($query) or die (mysql_error());
$AffectedRows = mysql_affected_rows($db_cnx, $db_slc);
if ($AffectedRows !=0)
{
print("<h3> Record aggiornato!!!!</h3>");
print("<h3><a href=\"modCan.php\">torna alla lista</a></h3>");
}
mysql_close($db_slc);
}
?>
</body>
</html>

e come risultato di errore mi da:
Notice: Undefined index: confirm in C:\xampp\htdocs\autopalmitessa\modify.php on line 8

Notice: Undefined index: marca in C:\xampp\htdocs\autopalmitessa\modify.php on line 51

Notice: Undefined index: modello in C:\xampp\htdocs\autopalmitessa\modify.php on line 52

Notice: Undefined index: km in C:\xampp\htdocs\autopalmitessa\modify.php on line 53

Notice: Undefined index: categoria in C:\xampp\htdocs\autopalmitessa\modify.php on line 54

Notice: Undefined index: pz in C:\xampp\htdocs\autopalmitessa\modify.php on line 55

Notice: Undefined index: anno in C:\xampp\htdocs\autopalmitessa\modify.php on line 56

Notice: Undefined index: optional in C:\xampp\htdocs\autopalmitessa\modify.php on line 57

Notice: Undefined index: ft1 in C:\xampp\htdocs\autopalmitessa\modify.php on line 58

Notice: Undefined index: ft2 in C:\xampp\htdocs\autopalmitessa\modify.php on line 59

Notice: Undefined index: ft3 in C:\xampp\htdocs\autopalmitessa\modify.php on line 60

Notice: Undefined index: ft4 in C:\xampp\htdocs\autopalmitessa\modify.php on line 61
No database selected
uffa mi sento proprio una capra!!!! dove sbaglio