php - 我的 PHP 脚本中出现 undefined variable 错误

Question

下面的代码有什么问题吗？请帮帮我。

我想将数据库中的管理员 ID 和密码与普通用户的登录 ID 和密码进行匹配，并进一步希望将控制权转移到相应的表单。

当我运行此代码时，它会出现以下错误:

Notice: Undefined variable: userstatus in C:\xampp\htdocs\xampp\Test\HRMS\extract.php on line 25

Notice: Undefined variable: usertype in C:\xampp\htdocs\xampp\Test\HRMS\extract.php on line 30

$query1="select user_type,user_staus from `user_info` where name='$username' and  
password='$password'";
$fetched=mysql_query($query1);

while($record=mysql_fetch_assoc($fetched))
{
    while(each($record))
    { 
        $usertype=$record["user_type"];
        $userstatus=$record["user_staus"];
    }//closing of 1st while loop
}//closing of 2nd while loop

if($userstatus==1) //if is logged in already
{
    echo "Please login after some time";
    exit();
}

if($usertype == 0) // if user is not an admin
{
    $query1="select * from `user_info` where name='$username' and  password='$password'";
    $result = mysql_query($query1);
    if(mysql_num_rows($result) == 1) 
    {
        header("Location: user_form.php");
    }
}
else if($usertype == 1) //if the user is a normal user
{
    header("Location: admin_form.php");
}
else 
{
    echo "please register to login";
}   

谁能帮我找出问题所在吗？

Answer 1

您的代码存在很多问题，您收到错误的主要原因是 $usertype 和 $userstatus 未预定义且未验证。
但在我看来，这不是您的代码的主要问题。

我想问你几个问题:

• 如果需要获取单行，为什么要创建两个循环？
• 如果您已经知道答案，为什么还要查询数据库两次？
• 您是否使用 mysql_real_escape_string 转义 $username 和 $password 中的不良字符方法？

以下是此代码的示例:

$query1 = "SELECT user_type,user_staus FROM `user_info` WHERE name='{$username}' AND password='{$password}' LIMIT 1";

$fetched = mysql_query($query1);

//check if record exists otherwise you would receive another notice that can 
//break redirect functionality
if (mysql_num_rows($fetched))
{
    $record = mysql_fetch_assoc($fetched);

    // make sure that value is integer
    if ((int)$record["user_staus"])
    {
        exit("Please login after some time");
    }
    else
    {
        $url = (bool)$record["user_type"] ? 'admin_form.php' : 'user_form.php';

        header("Location: {$url}");

        exit(0);
    }

}
else
{
    echo "please register to login";
}

更新
正如 nikc.org 建议的，删除了第三级 if 嵌套并替换为三元比较