不能同时插入和更新

Question

我有下面的代码，但我不明白为什么它不起作用。问题是我可以用它插入 post，但是当我尝试更新 post 时，它创建了一个新页面而不是更新。

我曾尝试从 if(isset($_POST['id']) != 'null') 中删除 isset 并且更新有效，但是插入不再有效。

知道我的代码有什么问题吗？谢谢

    <?php 

        if(isset($_POST['submitted']) == 1) 
        {

            $title = mysqli_real_escape_string($dbc, $_POST['title']);
            $header = mysqli_real_escape_string($dbc, $_POST['header']);
            $body = mysqli_real_escape_string($dbc, $_POST['body']);

            if(isset($_POST['id']) != 'null')
            {
                $q = "UPDATE pages SET user = $_POST[user], title = '$title', header = '$header', body = '$body' WHERE id = $_GET[id]";
            }
            else
            {
                $q = "INSERT INTO pages (user, title, header, body) VALUES ($_POST[user], '$title', '$header', '$body')";
            }


            $r = mysqli_query($dbc, $q);

            if($r)
            {
                $message = '<p>Page was added!</p>';
            } 
            else 
            {

                $message = '<p>Page could not be added because:</p>'.mysqli_error($dbc);
                $message .= '<p>'.$q.'</p>';
            }

        }
    ?>

Answer 1

试试这个：

if(isset($_POST['id']) AND $_POST['id'] != 'null')

Answer 2

您正在使用post并同时获得。首先查看是post还是get。然后简单地做 isset() check

<?php 

    if(isset($_POST['submitted']) == 1) 
    {

        $title = mysqli_real_escape_string($dbc, $_POST['title']);
        $header = mysqli_real_escape_string($dbc, $_POST['header']);
        $body = mysqli_real_escape_string($dbc, $_POST['body']);

        if(isset($_GET['id']) && $_GET['id']!="")

        {
            $q = "UPDATE pages SET user = $_POST[user], title = '$title', header = '$header', body = '$body' WHERE id = $_GET[id]";
        }

        else

        {
            $q = "INSERT INTO pages (user, title, header, body) VALUES ($_POST[user], '$title', '$header', '$body')";
        }


        $r = mysqli_query($dbc, $q);

        if($r)
        {
            $message = '<p>Page was added!</p>';
        } 

        else 
        {

            $message = '<p>Page could not be added because:</p>'.mysqli_error($dbc);
            $message .= '<p>'.$q.'</p>';
        }

    }
?>

Answer 3

use this code:  if(isset($_POST['id'] && $_POST['id']!= '')

不能同时插入和更新

Can't insert and update at the same time

php

mysql

mysqli

content-management-system

sql-insert