带有链接按钮的 HTML 表中的 PHP MySQL DELETE 行

Question

我已经看了一段时间了，我所做的只是用 mysql 学习 PHP，之前没有任何编程经验，所以请多多关照。我需要从表中删除整行。该表位于 list.php 中，并且有一个重定向到 delete.php 的删除按钮。但它所做的一切都是将我重定向到一个空白页面，其中的 url 类似于 "delete.php?id=4"，具体取决于行 ID，这似乎是正确的。

这是connect.php:

<?php 
$server = "localhost";
$db_user = "root";
$db_pass = "";
$db_name = "school";

$db_conn = mysqli_connect($server, $db_user, $db_pass, $db_name);

$connect_error = 'Sorry, we are experiencing connection problems';

mysql_connect('localhost', 'root', '') or die($connect_error);
mysql_select_db('school') or die($connect_error);

?>

这是 delete.php :

<?php 
if(isset($_GET['ID'])){
    $courseID = $_GET['ID'];
    $sql_delete = "DELETE FROM Courses WHERE ID = $courseID";       
    print ($sql_delete);        
        $result = mysqli_query($db_conn,$sql_delete);
    if($result) {
        echo "Congratulations. You have deleted this course succesfully.";
        header('location:list.php');
    } else {
        echo "Error";
    error_reporting(E_ALL ^ E_DEPRECATED);
    }

}
?>

注意“print ($sql_delete);”，它也不打印任何内容。我能想到的是我使用 $_GET 请求 ID 的方式有问题，但我无法理解它。当我运行时

"DELETE FROM Courses WHERE ID = 4;"

在 xampp 的 mysql 模块中，它可以工作。嗯……好吧。

好的，我补充一下: 这实际上是我在 list.php 中的删除按钮，它根据类(class) ID 为我提供了一个基于表行号的 URL。

<?php echo "<td><a href=\"delete.php?id=$row[ID]\">Delete</a>";?>

Answer 1

连接.php

    $server = "localhost";
    $db_user = "root";
    $db_pass = "";
    $db_name = "school";
    $db_conn = mysqli_connect($server, $db_user, $db_pass, $db_name);

删除.php

if(isset($_GET['ID'])){
  $courseID = $_GET['ID'];
  $sql_delete = "DELETE FROM Courses WHERE ID = $courseID";        
  $result = mysqli_query($db_conn,$sql_delete);
  if(mysqli_affected_rows($db_conn)>0) {
      header('location:list.php?result=success');
  } else {
     header('location:list.php?result=fail');
  }
 }

list.php(删除按钮在哪里)

<?php
if(isset($_GET['result'))
{
if($_GET['result']=='success')
{

    echo "Congratulations. You have deleted this course succesfully.";
}
else{
     echo "error";
  }
}
?>
(Delete button)
<a href="delete.php?ID=5" >Delete</a>