edit.php ( Data Siswa )

<?php
 include 'koneksi.php';
 if(!isset($_GET['nis'])){
 die("Error: NIS Tidak Dimasukkan");
 }
 $query = $db->prepare("SELECT * FROM `tbl_siswa` WHERE nis = :nis");
 $query->bindParam(":nis", $_GET['nis']);
 $query->execute();
 if($query->rowCount() == 0){
 die("Error: NIS Tidak Ditemukan");
 }else{
 $data = $query->fetch();
 }
 if(isset($_POST['submit'])){
 $nama = htmlentities($_POST['nama']);
 $alamat = htmlentities($_POST['alamat']);
 $kelas = htmlentities($_POST['kelas']);
 $query = $db->prepare("UPDATE `tbl_siswa` SET `nama`=:nama,`alamat`=:alamat,`kelas`=:kelas WHERE nis=:nis");
 $query->bindParam(":nama", $nama);
 $query->bindParam(":alamat", $alamat);
 $query->bindParam(":kelas", $kelas);
 $query->bindParam(":nis", $_GET['nis']);
 $query->execute();
 header("location: index.php");
 }
?>

<!DOCTYPE html>
<html>
 <head>
 <title>CRUD PDO quetkomputer.com </title>
 <meta charset="utf-8">
 </head>
 <body bgcolor="#CCCCCC">
 <h2><p align="center">EDIT DATA</p></h2>
 <form method="post">
 <table width="546" border="0" cellpadding="0" cellspacing="0" bgcolor="#FFFFFF" align="center">
 <tr>
 <td width="189" height="20"> </td>
 <td width="26"> </td>
 <td width="331"> </td>
 </tr>
 <tr>
 <td height="27" align="right" valign="middle">NIS</td>
 <td align="center" valign="top">:</td>
 <td valign="middle">
 <input type="text" name="nis" value="<?php echo $data['nis'] ?>" readonly="readonly">
 </td>
 </tr>
 <tr>
 <td height="27" align="right" valign="middle">Nama</td>
 <td align="center" valign="top">:</td>
 <td valign="middle"><label>
 <input type="text" name="nama" value="<?php echo $data['nama'] ?>">
 </label></td>
 </tr>
 <tr>
 <td height="27" align="right" valign="middle">Alamat</td>
 <td align="center" valign="top">:</td>
 <td valign="middle"><label>
 <input name="alamat" type="text" size="50" value="<?php echo $data['alamat'] ?>">
 </label></td>
 </tr>
 <tr>
 <td height="27" align="right" valign="middle">Kelas</td>
 <td align="center" valign="top">:</td>
 <td valign="middle"><label>
 <input name="kelas" type="text" size="50" value="<?php echo $data['kelas'] ?>">
 </label></td>
 </tr>
 <tr>
 <td height="42"> </td>
 <td> </td>
 <td><input type="submit" name="submit" value="EDIT"></td>
 </tr>
 </table>
 </form><p align="center"><a href=https://www.questkomputer.com/#>www.questkomputer.com</a></p>
 </body>
</html>