未定义的索引和无效的 foreach(）参数 php

我有一个页面，显示用户已保存到MYSQL数据库的项目，并将其与复选框一起回显。我希望当用户单击此复选框并单击保存按钮时，记录将被删除，但我的标题中遇到了错误。

显示假日表单。

        <form action="deleteProcess.php">
<?php
        foreach($db->query($sql) as $row)
        {
            echo "<p>" . $row['title'] . "<br '>" . 
                         $row['description'] . "<br '>" . 
                         $row['link'] . "<br '>" .
                         $row['pubDate'] . 
                         "<input type='checkbox' name='del[]' value='$row/['title'/]'/>" . 
                         "</p>";    
        }
?>
        <input type="submit" name="delete" value="submit" />
        </form>

删除过程.php

foreach($_POST['del'] as $check_value)
        {
            //takes session value and assigns it to a variable so that when a holiday is saved it can be distinguished by user
            $user = $_SESSION['name'];
            //assign the value of previous checkbox to $check
            $check = $check_value;
            //assign xpath query to variable $fav
            $fav = "channel/item [title = '"$check'"]";
            //loads instance of xml file as $holidayDoc
            $holidayDoc = simplexml_load_file('holidays.xml');
            //executes xpath search within holidays.xml and results stored in $favourites
            $favourites = $holidayDoc->xpath($fav);
        //for each element of the associative array $favourites, key will be referred to as $currentFav. 
        foreach($favourites as $currentFav)
        {
            echo "{$currentFav->link}". "<br '>";
            echo "{$currentFav->title}". "<br '>";
            echo "{$currentFav->description}". "<br '>";
            echo "{$currentFav->pubDate} ". "<br '>";
            //sql statement that states which values will be inserted into which column
            $sql = "DELETE FROM `saved_holidays` (`subscriberID`, `link`, `pubDate`, `title`, `description`) 
        VALUES ('$user', '$currentFav->link', '$currentFav->pubDate', '$currentFav->title', '$currentFav->description')";
            //connect to database then execute the sql statement.
            $db->exec($sql);
            //close connection to the database
            $db = null;

错误显示在foreach($_POST['del'] as $check_value)行，我不明白为什么它不起作用，任何帮助将不胜感激。

注意：未定义的索引：del in /var/www/vhosts/numyspace.co.uk/web_users/home/~unn_w11026991/public_html/Ass/deleteProcess.php 在第 14 行
警告：为 foreach（）提供的参数无效 /var/www/vhosts/numyspace.co.uk/web_users/home/~unn_w11026991/public_html/Ass/deleteProcess.php 在第 14 行

您的del复选框根本没有从表单中发布。您需要向表单添加method="post"。

<form action="deleteProcess.php" method="post">

您应该首先检查是否设置了 $_POST['del']，因为如果没有选中复选框，它就不会被选中。

if(isset($_POST['del'])){
    foreach($_POST['del'] as $del){}
}

您可以通过 $_POST 访问复选框值，但您的表单标签没有定义方法！你必须设置<form method="POST">，否则你必须使用$_GET['del']

<form action中缺少method="post"。

此外，用于删除的 SQL 语法不正确。从数据库中删除记录时，无需指定列。删除整个记录。

删除语法为：

DELETE FROM table_name WHERE condition

您的表单中缺少method="post"，因此没有发布任何内容，这是您的问题。

这个错误很清楚。

$_POST['del']

不存在，因为del不是已发布表单中的有效字段。

如果del是复选框的名称，则首先必须通过向表单添加post action来检索它们

未定义的索引和无效的 foreach(） 参数 php

undefined index and invalid foreach() argument php