今天学习了下php 写了个php  登录mysql 验证的代码呵呵
index.html  //登录页面
Name: 
Pass: 
welcome.php //验证页面
include 'db.php';
$name = $_POST['name'];
$pwd = $_POST['Pass'];  //这边都知道，获取传送过来的用户名和密码
$link = mysql_connect("$host","$user","$pass");
if(!$link){
echo "数据库连接失败！";
mysql_error();
}       //连接数据库，多写一个mysql_errro()绝对有好处，让你知道在数据库连接上有没有出错及出错信息！
mysql_select_db("my_db");
$exec = "SELECT * FROM user WHERE name='$name'";      //sql语句，查询用户名称！
$result = mysql_query($exec);
$rows = mysql_num_rows($result);
if($rows>0){
$row = mysql_fetch_assoc($result);
$lname=$row['lname'];
$rname=$row['rname'];
$Pass=$row['Pass'];
if($Pass==$pwd){
session_start();
$_SESSION['olname']=$lname;
$_SESSION['olrname']=$rname;   //上面几段就是密码效验，都比较简单，哈哈！~
echo "用户登陆成功!";
echo "
登陆用户是：".$rname."
";
header("refresh:5;url=lrm.html"); //5秒跳转到用户中心
}else{
echo "用户登陆失败！
";
echo "用户名或密码不正确！！";
header("refresh:5;url=lrm.html"); //5秒跳转到登录页面
}
}else{
echo "用户登陆失败！
";
echo "当前用户不存在！";
header("refresh:5;url=index.html"); //5秒跳转到登录页面
}
?>
简单的数据库
数据库名字 my_db  表user
然后进行登录测试...
高手们  别笑话啊！！！

首先，目前在产品环境可用的MySQL 版本(指4.0.x 和4.1.x )中，只有InnoDB 引擎才允许使用外键，所以，我们的数据表必须使用InnoDB 引擎。 下面，我们先创建以下测试用数据库表：CODE:[Copy to clipboard]CREATE TABLE `roottb` (
`id` INT(11) UNSIGNED AUTO_INCREMENT NOT NULL,
`data` VARCHAR(100) NOT NULL DEFAULT '',
PRIMARY KEY (`id`)
) TYPE=InnoDB;
CREATE TABLE `subtb` (
`id` INT(11) UNSIGNED AUTO_INCREMENT NOT NULL,
`rootid` INT(11) UNSIGNED NOT NULL DEFAULT '0',
`data` VARCHAR(100) NOT NULL DEFAULT '',
PRIMARY KEY (`id`),
INDEX (`rootid`),
FOREIGN KEY (`rootid`) REFERENCES roottb(`id`) ON DELETE CASCADE
) TYPE=InnoDB; 注意：1 、必须使用InnoDB 引擎；2 、外键必须建立索引(INDEX )；3 、外键绑定关系这里使用了“ ON DELETE CASCADE” ，意思是如果外键对应数据被删除，将关联数据完全删除，更多信息请参考MySQL 手册中关于InnoDB 的文档； 好，接着我们再来插入测试数据：CODE:[Copy to clipboard]INSERT INTO `roottb` (`id`,`data`)
VALUES ('1', 'test root line 1'),
('2', 'test root line 2'),
('3', 'test root line 3');
INSERT INTO `subtb` (`id`,`rootid`,`data`)
VALUES ('1', '1', 'test sub line 1 for root 1'),
('2', '1', 'test sub line 2 for root 1'),
('3', '1', 'test sub line 3 for root 1'),
('4', '2', 'test sub line 1 for root 2'),
('5', '2', 'test sub line 2 for root 2'),
('6', '2', 'test sub line 3 for root 2'),
('7', '3', 'test sub line 1 for root 3'),
('8', '3', 'test sub line 2 for root 3'),
('9', '3', 'test sub line 3 for root 3'); 我们先看一下当前数据表的状态：CODE:[Copy to clipboard]mysql>; show tables;
+----------------+
| Tables_in_test |
+----------------+
| roottb |
| subtb |
+----------------+
2 rows in set (0.00 sec)
mysql>; select * from `roottb`;
+----+------------------+
| id | data |
+----+------------------+
| 1 | test root line 1 |
| 2 | test root line 2 |
| 3 | test root line 3 |
+----+------------------+
3 rows in set (0.05 sec)
mysql>; select * from `subtb`;
+----+--------+----------------------------+
| id | rootid | data |
+----+--------+----------------------------+
| 1 | 1 | test sub line 1 for root 1 |
| 2 | 1 | test sub line 2 for root 1 |
| 3 | 1 | test sub line 3 for root 1 |
| 4 | 2 | test sub line 1 for root 2 |
| 5 | 2 | test sub line 2 for root 2 |
| 6 | 2 | test sub line 3 for root 2 |
| 7 | 3 | test sub line 1 for root 3 |
| 8 | 3 | test sub line 2 for root 3 |
| 9 | 3 | test sub line 3 for root 3 |
+----+--------+----------------------------+
9 rows in set (0.01 sec) 嗯，一切都正常，好，下面我们要试验我们的级联删除功能了。 我们将只删除roottb 表中id 为2 的数据记录，看看subtb 表中rootid 为2 的相关子纪录是否会自动删除：CODE:[Copy to clipboard]mysql>; delete from `roottb` where `id`='2';
Query OK, 1 row affected (0.03 sec)
mysql>; select * from `roottb`;
+----+------------------+
| id | data |
+----+------------------+
| 1 | test root line 1 |
| 3 | test root line 3 |
+----+------------------+
2 rows in set (0.00 sec)
mysql>; select * from `subtb`;
+----+--------+----------------------------+
| id | rootid | data |
+----+--------+----------------------------+
| 1 | 1 | test sub line 1 for root 1 |
| 2 | 1 | test sub line 2 for root 1 |
| 3 | 1 | test sub line 3 for root 1 |
| 7 | 3 | test sub line 1 for root 3 |
| 8 | 3 | test sub line 2 for root 3 |
| 9 | 3 | test sub line 3 for root 3 |
+----+--------+----------------------------+
6 rows in set (0.01 sec) 嗯，看subtb 表中对应数据确实自动删除了，测试成功。 结论：在MySQL 中利用外键实现级联删除成功！

今天学习了下php 写了个php  登录mysql 验证的代码呵呵
index.html  //登录页面
Name: 
Pass: 
welcome.php //验证页面
include 'db.php';
$name = $_POST['name'];
$pwd = $_POST['Pass'];  //这边都知道，获取传送过来的用户名和密码
$link = mysql_connect("$host","$user","$pass");
if(!$link){
echo "数据库连接失败！";
mysql_error();
}       //连接数据库，多写一个mysql_errro()绝对有好处，让你知道在数据库连接上有没有出错及出错信息！
mysql_select_db("my_db");
$exec = "SELECT * FROM user WHERE name='$name'";      //sql语句，查询用户名称！
$result = mysql_query($exec);
$rows = mysql_num_rows($result);
if($rows>0){
$row = mysql_fetch_assoc($result);
$lname=$row['lname'];
$rname=$row['rname'];
$Pass=$row['Pass'];
if($Pass==$pwd){
session_start();
$_SESSION['olname']=$lname;
$_SESSION['olrname']=$rname;   //上面几段就是密码效验，都比较简单，哈哈！~
echo "用户登陆成功!";
echo "
登陆用户是：".$rname."
";
header("refresh:5;url=lrm.html"); //5秒跳转到用户中心
}else{
echo "用户登陆失败！
";
echo "用户名或密码不正确！！";
header("refresh:5;url=lrm.html"); //5秒跳转到登录页面
}
}else{
echo "用户登陆失败！
";
echo "当前用户不存在！";
header("refresh:5;url=index.html"); //5秒跳转到登录页面
}
?>
简单的数据库
数据库名字 my_db  表user
然后进行登录测试...
高手们  别笑话啊！！！

$uname=$_POST["username"];
$pwd=$_POST["password"];
$link = mysql_connect(‘localhost‘, ‘root‘, ‘123456‘)
or die(‘Could not connect: ‘ . mysql_error());
mysql_select_db(‘ruida‘) or die(‘Could not select database‘);
// 执行 SQL 查询
$query = ‘SELECT * FROM user‘;
$result = mysql_query($query) or die(‘Query failed: ‘ . mysql_error());
while($row=mysql_fetch_array($result)){
if($uname==$row[‘username‘] && $pwd==$row[‘password‘])
{
//页面跳转
}
else
echo ‘error!‘;}
// 释放结果集
mysql_free_result($result);
// 关闭连接
mysql_close($link);
?>
原文：http://www.jb51.net/article/22724.htm