Question

在此代码中，我没有任何错误消息，但它不会删除数据。顺便说一下，数据库有很多记录，所有字段的名称都是正确的。

<?php

if ($connect = mysqli_connect('localhost', 'root', 'adminpass', 'flip'))
    {
    $id = $_GET['id'];
    $sql = "SELECT * FROM threads ORDER BY id DESC";
    $query = mysqli_query($connect, $sql);
    $num = mysqli_num_rows($query);
    }

?>

    <form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="POST" >

    <table border="1" width="400" cellpadding="0" cellspacing="0">
    <tr>
    <td>#</td>
    <td>id</td>
    <td>subject</td>
    </tr>

    <?php

while ($row = mysqli_fetch_array($query))
    {
?>

    <tr>
    <td> <input type="checkbox" name="checkbox[]" value="<?php echo $row['id'] ?>"></td>
    <td><?php echo $row['id'] ?></td>
    <td><?php echo $row['topic'] ?></td>
    </tr>   

<?php
    }
?>
    <input type="submit" name="delete" value="delete" >

<?php

if (isset($delete))
    {
    for ($i = 0; $i < $num; $i++)
        {
        $del_id = $checkbox[$i];
        $sql2 = "DELETE FROM threads WHERE id='$del_id'";
        $query2 = mysqli_query($connect, $sql2);
        }

    if ($query2)
        {
        echo "<meta http-equiv=\"refresh\" content=\"0;URL=delete.php\">";
        }
    }

mysqli_close($connect);
?>
</table>

</form>

它有什么问题？

Answer 1

你可以试试这个：

<?php

/* ESTABLISH CONNECTION */

$connect=mysqli_connect("localhost","root","adminpass","flip");

if(mysqli_connect_errno()){

echo "Error".mysqli_connect_error();
}

if(isset($_POST['delete'])){ /* IF DELETE IS CLICKED */

$checkbox=$_POST['checkbox'];
$hiddencounter=mysqli_real_escape_string($connect,$_POST['hiddencounter']); /* PREVENT A BIT OF SQL INJECTION */

for($i=0;$i<$hiddencounter;$i++){ /* FOR LOOP BASED ON THE NUMROWS BELOW */

   if(!empty($checkbox[$i])){ /* IF THE CHECKBOX IS TICKED */
        $del_id=mysqli_real_escape_string($connect,$checkbox[$i]);  /* PREVENT A BIT OF SQL INJECTION */
        $sql2="DELETE FROM threads WHERE id='$del_id'";
        $query2=mysqli_query($connect,$sql2); /* IMPLEMENT THE DELETE QUERY */

   }

} /* END OF FOR LOOP */

echo "<meta http-equiv=\"refresh\" content=\"0;URL=delete.php\">";

} /* END OF ISSET DELETE */

?>

<form action="" method="POST" > <?php /* YOU CAN LEAVE THE ACTION BLANK, TO SUBMIT THE FORM ON THE PAGE ITSELF */ ?>

<table border="1" width="400" cellpadding="0" cellspacing="0">
<tr>
<td>#</td>
<td>id</td>
<td>subject</td>
</tr>

<?

$sql="SELECT * FROM threads ORDER BY id DESC";
$query=mysqli_query($connect,$sql);
$num=mysqli_num_rows($query);

/* SUBMIT THE NUMBER OF ROWS QUERIED THROUGH HIDDEN INPUT */
echo "<input type='hidden' name='hiddencounter' value='$num'>";

while($row=mysqli_fetch_array($query)){ /* FETCH DATA */

?>

<tr>
<td><input type="checkbox" name="checkbox[]" value="<?php echo $row['id'] ?>"></td>
<td><?php echo $row['id'] ?></td>
<td><?php echo $row['topic'] ?></td>

</tr>   

<?
} /* END OF WHILE LOOP $QUERY */
?>

<input type="submit" name="delete" value="delete" >

<?php

mysqli_close($connect);

?>
</table>

</form>

解释您的代码无效的原因：

您的isset($delete)：$delete变量来自何处？
您的 for循环并不确定提交的复选框是否具有值。
您的<meta>重定向。它会在 for循环后重定向到 delete.php ，这就是您没有看到任何错误的原因。但是，如果您删除<meta>重定向，我很确定您会看到一些错误。
即使删除工作正常，您也不会立即看到结果，因为删除查询是在您提取数据之后。

Answer 2

您的变量中有错误：

if (isset($delete))

应该是：

   if (isset($_POST['$delete']))

Answer 3

我没有看到代码中设置$delete变量的位置。目前$delete未设置，因此if(isset($delete))为假。

对我而言，您似乎正在尝试使用Registered Globals。或者您忘记将$delete设置为$_GET[]或$_POST[]个变量之一。

＆＃34;警告自PHP 5.3.0开始，此功能已被弃用，自PHP 5.4.0起已被删除。＆＃34;

PHP manual - Security Globals

Predefined Variables

此代码中没有错误消息，但它不会删除字段

3 个答案: