第四讲注册功能

<meta charset="utf-8">

<?php 
	// 根据用户为关键字。若无则插入，否则进行修改
require_once('db_config.php'); 
if(isset($_POST['ok'])){
	$name = $_POST['name'];
	$pwd = md5($_POST['pwd']);
	$query_string = "select * from user where name='$name'";
		// 要锁表 
	$re = mysqli_query($link,$query_string);
	$num = mysqli_num_rows($re);
	if($num == 0){
		$type = "insert";
		$query_string = "insert into user(name,password) values('$name','$pwd')";
	}
	else{
		$type = "update";
		$query_string = "update user set password = '$pwd' where name='$name'";
	}
	$re1 = mysqli_query($link,$query_string);
	if(mysqli_error($link)==""){
		echo "操作".$type."成功";
	}
	else{
		echo '操作失败'.mysqli_error($link);
	}
}
else{
	$name ='';
	$pwd = '';
}
?>

<form action="" method="post">
	xm:<input type="text" name="name" value=""><br>
	pwd:<input type="password" name="pwd" value=""><br>
	<input type="submit" name="ok" value="ok">
</form>