assign

$id2 = $_POST['ID'];
$StudentID = $_POST['StudentID'];
$ClassID = $_POST['ClassID'];
/* if($db_found)
{ */
    foreach($_POST["selected"] as $value)
    {
        $id = substr($value, 8);

        $SQL= "UPDATE enroll
               SET StudentID ='$id', ClassID='$id2'";
               WHERE StudentID='$id'";
        mysql_query($SQL);

        mysql_query ("UPDATE enroll
               SET StudentID ='$id', ClassID='$id2'
               WHERE StudentID='$id'")
                or die(mysql_error());