php - Jquery sortable PDO update order -

i'm trying create sortable list updates pdo (php data objects). i've tried work out, although seems doesn't want update, , i'm unsure i've gone wrong. drag works fine, data seems work correct. doesn't update database.

main file jquery

 <ul id="sortable"> <?php     $sql = "select * ".$prefix."question enabled = 1 order sortby asc";     $stm = $dbh->prepare($sql);      $stm->execute();     $u = $stm->fetchall();      $count = 0;      foreach ($u $sup) {                       ?>     <li id="item-<?php echo $sup['id']; ?>"><?php echo $sup['title']; ?></li> <?php } ?> </ul>  <script src="https://code.jquery.com/jquery-1.12.4.js"></script> <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script> <script>   $('#sortable').sortable({     axis: 'y',     update: function (event, ui) {         var data = $(this).sortable('serialize');          // post server using $.post or $.ajax         $.ajax({             data: data,             type: 'post',             url: 'order.php'         });     } }); </script> 

php file [order.php] (connection database fine , works correctly)

<?php ob_start(); session_start(); $admin = true; require "inc/config.php";  $i = 0;  foreach ($_post['item'] $value) {     // execute statement:     // update [table] set [position] = $i [entityid] = $value     $sql = $dbh->prepare("update ".$prefix."question set sortby='".$i."' id=1");     $sql->execute();      $i++; }  ?> 

if see problem is, i'd appreciate it.

was able fix this. issue how getting config.php database.

rest of code works.