mysql更新，计算机说它工作但数据库没有变化

<?php 

  require('dbconnect.php');

  $indexno = $_POST['indexno'];
  $cevap = $_POST['cevap'];
  $cevapdate = gmdate("Y-m-d\TH:i:s\Z");
  $query = "UPDATE soru 
               SET cevap = '$cevap', 
                   cevapdate = '$cevapdate' 
             WHERE `index` = '$indexno'";

$link = mysql_query($query);
if(!$link) {
  die('not worked: ' . mysql_error());
} else {
  mysql_close($con);    
  echo 'worked';
}

?>

Outcome of this php code is "Worked." but there is no change in the database. The thing is Im trying to update the cevap and cevapdate fields on a row by index id.

You need to remove the single quotes from aroud the index. You should not put single quotes around a column name while writing a query. Write your query this way -

$query = "UPDATE soru SET cevap = '$cevap', cevapdate = '$cevapdate' WHERE index = '$indexno'";

You have to escape your rows/table with backticks, not single-quotes.

$query = "UPDATE `soru`
  SET `cevap` = '$cevap', `cevapdate` = '$cevapdate'
  WHERE `index` = '$indexno'";

Also, you should escape your user input to prevent SQL injections.