php中的登录和数据库连接代码

它不起作用，我花了几个小时半的时间试图找出原因。我的html索引文件中已经嵌入了表单，代码如下：

我想创建登录和注销会话

mysql数据库中的表如下所示

CREATE TABLE member ( id int(10) NOT NULL auto_increment, userName varchar(50) NOT NULL, passWord varchar(50) NOT NULL, PRIMARY KEY (id) ) ENGINE=MyISAM    utf8_general_ci  AUTO_INCREMENT=3 ;

<?php

    // Inialize session

    session_start();
    // Include database connection settings
    $hostname = 'localhost';        // Your MySQL hostname. Usualy named as 'localhost',        so you're NOT necessary to change this even this script has already     online on the   internet.
    $dbname   = 'database'; // Your database name.
    $username = 'root';             // Your database username.
    $password = '';                 // Your database password. If your database has no           password, leave it empty.

     // Let's connect to host
     mysql_connect($hostname, $username, $password) or DIE('Connection to host is failed,        perhaps the service is down!');
     // Select the database
      mysql_select_db($dbname) or DIE('Database name is not available!');


      // Retrieve username and password from database according to user's input
     $userName=mysql_real_escape_string($_POST['username']); 
     $password=mysql_real_escape_string($_POST['password']); 
     $passWord=md5($password); // Encrypted Password

       //*********retrieving data from Database**********

      $query = "SELECT * FROM member WHERE userName='$userName' and passWord='$passWord'";
      //$login = mysqli_query("SELECT userName,password FROM 'member' WHERE userName=          $_post['username'] AND passWord= $_post['password'])");
       // Check username and password match
      $res = mysql_query($query);

      $rows = mysql_num_rows($res);
      if ($rows==1) {
      // Set username session variable

      $_SESSION['userName'] = $_POST['username'];

     // Jump to secured page
      header("Location: securedpage.php");
     }
     else {
     // Jump to login page
     echo "user name and password not found";
     }
     exit;
     ?>

CREATE TABLE member（id int（10）NOT NULL auto_increment，userName varchar（50）NOT NULL，passWord varchar（50）NOT NULL，PRIMARY KEY（id））ENGINE=MyISAM utf8_general_ci auto_increment=3；
假设你只是为了学习而不是为了实际应用

您应该检查您的DB设置，注意所有的事情都准备好了，然后您需要一个表单，从那里您可以发布到这个php文件，下面是一个小的更新：

<?php

    session_start();
    $hostname = 'localhost';
    $dbname   = 'yourdatabase';
    $username = 'root'; 
    $password = 'yourpassword';
    mysql_connect($hostname, $username, $password) or DIE('Connection to host isailed, perhaps the service is down!');
    mysql_select_db($dbname) or DIE('Database name is not available!');

    $userName=mysql_real_escape_string($_POST['username']); 
    $passWord=md5(mysql_real_escape_string($_POST['password'])); 
    $query = "SELECT id FROM member WHERE userName='$userName' and  passWord='$passWord'";
    $res = mysql_query($query);
    $rows = mysql_num_rows($res);
    if ($rows==1) 
    {
        $_SESSION['userName'] = $_POST['username'];
        header("Location: securedpage.php");
    }
    else 
    {
        echo "user name and password not found";
        // TODO - replace message with redirection to login page
        //  header("Location: securedpage.php");
    }

这是代码。。。。修改并尝试

<?php
session_start();

$connect = mysql_connect('localhost', 'root', '') or die('Database could not connect');
$select = mysql_select_db('test', $connect) or die('Database could not select');

if (isset($_POST['submit'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    chckusername($username, $password);
}

function chckusername($username, $password){

    $check = "SELECT * FROM login WHERE username='$username'";
    $check_q = mysql_query($check) or die("<div class='loginmsg'>Error on checking Username<div>");

    if (mysql_num_rows($check_q) == 1) {
        chcklogin($username, $password);
    }
    else{
        echo "<div id='loginmsg'>Wrong Username</div>";
    }
}

function chcklogin($username, $password){

    $login = "SELECT * FROM login WHERE username='$username'  and password='$password'";
    $login_q = mysql_query($login) or die('Error on checking Username and Password');

    if (mysql_num_rows($login_q) == 1){
        echo "<div id='loginmsg'> Logged in as $username </div>"; 
        $_SESSION['username'] = $username;
        header('Location: member.php');
    }
    else {
        echo "<div id='loginmsg'>Wrong Password </div>"; 
        //header('Location: login-problem.php');
    }
}
?>

这里有很多危险信号-
mysql\uucode>弃用、纯文本密码存储、没有mysql根密码等等。我建议在谷歌搜索“PHP-mysql-login”后重新思考这一点，为什么你要使用MD5来运行自己的身份验证系统，这是一个严重的危险信号，如果不使用它，您可能已经实现了这一点？警告：您完全可以使用参数化的预处理语句，而不是手动生成查询。它们由或提供。永远不要相信任何形式的输入！即使您的查询仅由受信任的用户执行。切勿以明文或使用MD5/SHA1存储密码！仅存储使用PHP创建的密码哈希，然后可以使用进行验证。看一看这篇文章：了解更多关于你能详细说明你改变了什么，这样读者就不必做区分来找出问题所在吗？
<?php
session_start();

$connect = mysql_connect('localhost', 'root', '') or die('Database could not connect');
$select = mysql_select_db('test', $connect) or die('Database could not select');

if (isset($_POST['submit'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];
    chckusername($username, $password);
}

function chckusername($username, $password){

    $check = "SELECT * FROM login WHERE username='$username'";
    $check_q = mysql_query($check) or die("<div class='loginmsg'>Error on checking Username<div>");

    if (mysql_num_rows($check_q) == 1) {
        chcklogin($username, $password);
    }
    else{
        echo "<div id='loginmsg'>Wrong Username</div>";
    }
}

function chcklogin($username, $password){

    $login = "SELECT * FROM login WHERE username='$username'  and password='$password'";
    $login_q = mysql_query($login) or die('Error on checking Username and Password');

    if (mysql_num_rows($login_q) == 1){
        echo "<div id='loginmsg'> Logged in as $username </div>"; 
        $_SESSION['username'] = $username;
        header('Location: member.php');
    }
    else {
        echo "<div id='loginmsg'>Wrong Password </div>"; 
        //header('Location: login-problem.php');
    }
}
?>