php - 谁能帮我弄清楚这段代码有什么问题？

Question

<?php
$con = mysql_connect("localhost", "root", '');

if (!$con)
{
    die('Cannot make a connection');
}


mysql_select_db('yumbox_table', $con) or die('Cannot make a connection');



$username = $_POST['user_name'];
$password = $_POST['password'];
$type = $_POST['user_type'];

$data = mysql_query("SELECT * from users ") or die(mysql_error());

$info = mysql_fetch_array($data);

$count = mysql_numrows($info);

if ($count==1)
{
    echo ("Success!!");
}
else 
{
    echo ("BIG FRIGGIN FAILURE!!");
}

mysql_close($con);
?>

每当我尝试运行这段代码时，我都会收到这些漂亮的大错误消息:

( ! ) Notice: Undefined index: user_name in C:\wamp\www\login.php on line 14
Call Stack
#   Time    Memory  Function    Location
1   0.0008  370104  {main}( )   ..\login.php:0

( ! ) Notice: Undefined index: password in C:\wamp\www\login.php on line 15
Call Stack
#   Time    Memory  Function    Location
1   0.0008  370104  {main}( )   ..\login.php:0

( ! ) Notice: Undefined index: user_type in C:\wamp\www\login.php on line 16
Call Stack
#   Time    Memory  Function    Location
1   0.0008  370104  {main}( )   ..\login.php:0

( ! ) Warning: mysql_numrows() expects parameter 1 to be resource, array given in C:\wamp\www\login.php on line 22
Call Stack
#   Time    Memory  Function    Location
1   0.0008  370104  {main}( )   ..\login.php:0
2   0.0157  380104  mysql_numrows ( )   ..\login.php:22

我一直在绞尽脑汁试图找出这些问题背后的含义并修复它们，遗憾的是没有找到任何解决方案。有人可以帮忙吗？

Answer 1

要么 POST 不包含有问题的变量，要么您一开始就没有执行 POST。