php中存储用户ID和密码到mysql数据库的方法

CREATE TABLE tbl_auth_user (
user_id VARCHAR(10) NOT NULL,
user_password CHAR(32) NOT NULL,
PRIMARY KEY (user_id)
);
INSERT INTO tbl_auth_user (user_id,user_password) VALUES ('theadmin',PASSWORD('chumbawamba'));
INSERT INTO tbl_auth_user (user_id,user_password) VALUES ('webmaster',PASSWORD('webmistress'));

// 我们必须永远不会忘记启动会话
session_start();
$errorMessage = '';
if (isset($_POST['txtUserId']) && isset($_POST['txtPassword'])) {
include 'library/config.php';
include 'library/opendb.php';
$userId = $_POST['txtUserId'];
$password = $_POST['txtPassword'];
// 检查用户id和密码组合存在于数据库
$sql = "SELECT user_id
FROM tbl_auth_user
WHERE user_id = '$userId'
AND user_password = PASSWORD('$password')";
$result = mysql_query($sql)
or die('Query failed. ' . mysql_error());
if (mysql_num_rows($result) == 1) {
// sessionthe设置用户id和密码匹配,
// 设置会话
$_SESSION['db_is_logged_in'] = true;
// 在登录后我们转到主页
header('Location: main.php');
exit;
} else {
$errorMessage = 'Sorry,wrong user id / password';
}
include 'library/closedb.php';
}
?>

session_start();
//是一个访问这个页面登录呢?
if (!isset($_SESSION['db_is_logged_in'])
|| $_SESSION['db_is_logged_in'] !== true) {
// 没有登录,返回到登录页面
header('Location: login.php');
exit;
}
?>

session_start();
// 如果用户已登录,设置会话
if (isset($_SESSION['db_is_logged_in'])) {
unset($_SESSION['db_is_logged_in']);
}
// 现在,用户登录,
// 去登录页面
header('Location: login.php');
?>