update query not working in php

<?php

if(isset($_POST["edit_submit"]))
 {

  $sr_no=$_POST['sr_no'];
  $username=$_POST['username'];
  $first_name=$_POST['first_name'];
  $last_name=$_POST['last_name'];
  $img=$_FILES['uploadfile']['name'];
  $email=$_POST['email'];
  $mobno=$_POST['mobno'];
  $country=$_POST['country'];
  $city=$_POST['city'];
  $address=$_POST['address'];
  $zip=$_POST['zip'];
  $sex=$_POST['sex'];

  $target_path      ="components/com_test/views/default/tmpl/uploaded-images/";
  $target_path      =   $target_path . basename( $_FILES['uploadfile']['name']);

  }

  $Update = "update proj_tbl set sr_no='$sr_no',username='$username',first_name='$first_name',last_name='$last_name',img='$img',
  email='$email',mobno='$mobno',country='$country',city='$city',address='$address',zip='$zip',sex='$sex' where sr_no='$sr_no'";
  $updatesql = mysql_query($Update) or die(mysql_error());


?>