Modification des données

Bonjour,

j'ai un crée un code pour modifier des données insérées dans ma base de donnée..mais rien ne se modifié..voici le code:

<?php
session_start();

$ref_no=$_SESSION['ref_no'];

<form name="remplir" method="POST" action="edit.php">
<input type=hidden name="mail_req" value=<?php echo $_SESSION['email'] ?>>
<div class="mama">
<table>

<tr><td width=20% style='font-weight: bold;'> REF NO :</td>
<td><?php echo($_SESSION['ref_no']);?></td>

<td><input type="text" name="date" value="<?php echo $_SESSION['date'];?>" class="entryfont2"></td>
</tr>
<tr>
<td width=20% style='font-weight: bold;'><span> Local currency :</span></td>
<td> <input type="text" name="inv_number" class="entryfont2" value=<?php echo $_SESSION['currency']?>></td>

<td width=20% style='font-weight: bold;'><span> Invoice number :</span></td>

<td> <input type="text" name="inv_number" class="entryfont2" value=<?php echo $_SESSION['inv_number']?>></td>


<td width=20% style='font-weight: bold;'><span> Requesting center :</span></td>

<td><input type="text" name="req_center" class="entryfont2" value=<?php echo $_SESSION['req_center']?>></td>

</tr>
<tr>

<td width=20% style='font-weight: bold;'><span> Selling company :</span></td>
<td><input type="text" name="selling_com" class="entryfont2" value=<?php echo $_SESSION['selling_com']?>> </td>

<td width=20% style='font-weight: bold;'><span> Purchasing company :</span></td>
<td><input type="text" name="purchasing_com" class="entryfont2" value=<?php echo $_SESSION['purchasing_com']?>></td>

<td width=20% style='font-weight: bold;'><span> Receiving plant/center : </span></td>
<td><input type="text" name="receive_pc" class="entryfont2" value=<?php echo $_SESSION['receive_pc']?>></td>

</tr>

<tr>
<td width=20% style='font-weight: bold;'><span> Attention of Mr : </span></td>
<td><input type="text" name="attention" class="entryfont2" value=<?php echo $_SESSION['attention']?>></td>

</tr>
<tr><input type="submit" name="valider" value="continuer" class="envoi"></tr>
</table>

<?php



if(isset($_POST['currency']))
$currency=addslashes($_POST['currency']);
else $currency='';
if(isset($_POST['inv_number']))
$inv_number=addslashes($_POST['inv_number']);
else $inv_number='';
if(isset($_POST['req_center']))
$req_center=addslashes($_POST['req_center']);
else $req_center='';
if(isset($_POST['selling_com']))
$selling_com=addslashes($_POST['selling_com']);
else $selling_com='';
if(isset($_POST['purchasing_com']))
$purchasing_com=addslashes($_POST['purchasing_com']);
else $purchasing_com='';
if(isset($_POST['receive_pc']))
$receive_pc=addslashes($_POST['receive_pc']);
else $receive_pc='';
if(isset($_POST['attention']))
$attention=addslashes($_POST['attention']);
else $attention='';
if(isset($_POST['date']))
$date=addslashes($_POST['date']);
if(isset($_POST['mail_req']))
$mail_req=addslashes($_POST['mail_req']);


mysql_connect('localhost','root','')or die('Erreur de connexion '.mysql_error());
mysql_select_db('mabase') or die('Erreur de selection '.mysql_error());

if(isset($_POST['edit']))
{

$sq="UPDATE formulaire SET inv_number='$inv_number', req_center='$req_center', selling_com='$selling_com', purchasing_com='$purchasing_com', receive_pc='$receive_pc', attention='$attention' WHERE ref_no='$ref_no'";
$rq = mysql_query($sq) or die('Erreur SQL !'.$sq.'<br>'.mysql_error()) ;
if($rq)
{echo("modification réussite");}
else
{
echo("erreur");
}
}

if(isset($_POST['delete']))

{
$sql = "DELETE FROM formulaire WHERE ref_no='$ref_no'" ;
$sql = "DELETE FROM tableau WHERE ref_no='$ref_no'" ;

//exécution de la requête:
$requete = mysql_query( $sql) or die('Erreur SQL !'.$sql.'<br>'.mysql_error()) ;
if($requete)
{
echo("La suppression à été correctement effectuée") ;
}
else
{
echo("La suppression à échouée") ;
}


}
?>