php如何对表单数据进行批量修改？

//表单
<form>
............
<input name="Key[]" type="text" id="Key[]" value="<?php echo $rs->Fields(Key)->value;?>" size="5">
<input name="del_id[]" type="text" id="del_id[]" value="<?php echo $rs->Fields(id)->value;?>" size="5">
............
</form>

<?
$action=$_POST['action'];
if($action=='del'){
$rs=new COM("adodb.recordset");
for($i = 0; $i < count($_POST[Key]); $i ++){
$rs->open("UPDATE [Products] SET Key = ".$_POST[Key][$i]." where id = ".$_POST[del_id][$i]."",$conn,1,1);
}
echo "<script type='text/javascript'>alert('处理成功！');window.location.href='Productstj_Manage.php';</script>";
}    
?>