未选择获取错误数据库

Question

代码：

<?php
session_start();
$_SESSION['msg'] = "";
$con = mysql_connect('localhost','me','omglol');
mysql_select_db('test',$con);
$q = mysql_query(sprintf("select * from UserTable where (nick=\"%s\") AND (pass=SHA1(\"%s\"))",$_POST['nick'],$_POST['pass']),$con) or die(mysql_error());

在我看来这是对的。是的，我知道'test‘的存在。并包含UserTable。

首先，感谢rid将php4添加到我忘记的标记中:(

根据激光向导的建议，我执行了以下操作：(完整代码)：

<?php
session_start();
$_SESSION['msg'] = "";
$con = mysql_connect('localhost','me','omglol');
if(!$con)
{
    die("The connection to mysql server is not being made.");
}
$db = 'test';
$selected = mysql_select_db($db,$con);
if(!$selected)
{
    die(sprintf("Cannot use database %s.",$db));
}
//$q = mysql_query(sprintf("select * from UserTable where (nick=\"%s\") AND (pass=SHA1(\"%s\"))",$_POST['nick'],$_POST['pass']),$con) or die(mysql_error());
$q = mysql_query("select * from UserTable",$con) or die("The query statement still isn't working");
$row = mysql_fetch_assoc($q);
$dest=0;
if(mysql_num_rows($q)==0)
{
    //$testn = mysql_query(sprintf("select * from UserTable where nick=(\"%s\")",$_POST['nick']),$con);
        $testn = mysql_query("select * from Category",$con) or die("The 2nd query statement still isn't working");
        if(mysql_num_rows($testn)==0)
        {
               $_SESSION['msg'] = "Nick ".$_POST['nick']." was not found. Check spelling or <a href=\\\"register.php\\\">register</a>";
        }
        else
        {
                $_SESSION['msg'] = "Password incorrect";
        }
        if(isset($_SESSION['attempts']))
        {
                $_SESSION['attempts'] = $_SESSION['attempts'] + 1;
        }
        else
        {
                $_SESSION['attempts'] = 1;
        }
    mysql_free_result($q);
    mysql_free_result($testn);
        mysql_close($con);
    $dest = 'Location:http://cs4.sunyocc.edu/~me/onestopshop/login.php';
}
else
{
        $_SESSION['nick'] = $_POST['nick'];
    $_SESSION['email'] = $row['email'];
    mysql_free_result($q);
    mysql_close($con);
    $dest = 'Location:http://cs4.sunyocc.edu/~me/onestopshop/index.php';
}
header($dest);
exit();
?>

与上面的错误相同。所以设置了$con并且$selected读取为真，所以我不知道下一步要检查什么。我猜是mysql_select_db($db，$con)；也不是$testn仍然不能工作，但仍然读起来是真的？我不知道下一步该怎么做。

Answer 1

抛出一些die语句来测试连接，并确保它正在建立。除此之外，我会说注释掉您的查询行，看看这是否会导致问题。

$link = mysql_connect('localhost', 'mysql_user', 'mysql_password');
if (!$link) {
    die('Not connected : ' . mysql_error());
}

// make foo the current db
$db_selected = mysql_select_db('foo', $link);
if (!$db_selected) {
    die ('Can\'t use foo : ' . mysql_error());
}

Answer 2

如果您使用的是PDO 5.1.0，请忽略这些说明，使用>=：

<?php
    $conn = new PDO('mysql:host=localhost;dbname=test', 'user', 'pass');
    foreach($conn->query('SELECT * from TEST') as $row) {
        print_r($row);
    }
?>