diff --git "a/\351\273\216\345\205\264\350\211\257/20220525-session-cookie.md" "b/\351\273\216\345\205\264\350\211\257/20220525-session-cookie.md"
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+# 作业
+
+#### 链接mysql文件
+```php
+<?php
+error_reporting(E_ALL^E_WARNING);
+$conn=mysqli_connect("localhost","root","123456","student") or die("连接失败，错误为：".mysqli_connect_errno());
+mysqli_query($conn,"set names utf8");
+
+```
+
+#### 主页
+```php
+<?php
+include_once ('conn.php');
+$sql="select * from `user` ";
+$result=mysqli_query($conn,$sql);
+?>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>学生信息管理</title>
+</head>
+<body>
+<h1>学生信息管理</h1>
+<table border="1" width="300">
+    <tr>
+        <th>学号</th>
+        <th>姓名</th>
+        <th>成绩</th>
+        <th>操作</th>
+    </tr>
+    <?php
+    if(!mysqli_num_rows($result)) {//
+        echo "<tr align='center'><td colspan='4'>暂无数据！</td></tr>";
+    }else {
+    while ($row = mysqli_fetch_assoc($result)) {
+    ?>
+    <tr align="center">
+        <td><?php echo $row['id'];?></td>
+        <td><?php echo $row['name'];?></td>
+        <td><?php echo $row['score'];?></td>
+        <td><a href="edit.php?id=<?php echo $row['id'] ?>">修改</a>|
+            <a href="delete.php?id=<?php echo $row['id'] ?>">删除</a></td>
+    </tr>
+        <?php
+     }
+    }
+    ?>
+</table>
+<a href="add.php">添加信息</a>
+</body>
+</html>
+```
+
+#### 添加信息
+###### add文件
+```php
+<?php
+
+?>
+
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>添加学生信息</title>
+</head>
+
+<h1>添加学生信息</h1>
+<form action="save.php" method="post" >
+<table border="1" width="300">
+
+    <tr>
+        <th>姓名</th><td><input type="text" name="name"></td>
+    </tr>
+
+    <tr>
+        <th>成绩</th><td><input type="text" name="score"></td>
+    </tr>
+    <tr>
+        <td colspan="2" align="center"><input type="submit" name='submit' value="提交">&nbsp;&nbsp;&nbsp;&nbsp; <input type="reset" value="取消"></td>
+
+    </tr>
+</table>
+    <a href="li.php">返回</a>
+</form>
+
+</html>
+
+```
+###### save文件
+```php
+<?php
+include_once ('conn.php');
+
+ if(!isset($_POST['submit'])){
+     die("非法访问");
+ }
+
+ $name=$_POST['name'];
+ $score=$_POST['score'];
+
+ $sql="insert into `user` (`name`,`score`)values ('$name',$score)";
+ $result=mysqli_query($conn,$sql);
+if($result){
+    echo "添加成功！<a href='li.php'>返回首页</a>";
+}else{
+    echo "添加失败！";
+}
+```
+
+#### 修改数据
+###### edit文件
+```php
+<?php
+include_once ("conn.php");
+if(!isset($_GET['id'])){
+    die("非法访问！");
+}
+$id=$_GET['id'];
+$sql = "select * from `user` where `id`=$id";// 从数据库查询id为$book_id的数据
+$result = mysqli_query($conn,$sql);
+$row = mysqli_fetch_assoc($result);
+?>
+<html>
+<head>
+    <title>修改信息</title>
+
+</head>
+<h1>修改信息</h1>
+<form action="update.php" method="post">
+    <table border="1" width="300">
+        <tr>
+            <th>姓名</th><td><input type="text" name="name" value="<?php echo $row['name'] ?>"></td>
+        </tr>
+        <tr>
+            <th>成绩</th><td><input type="text" name="score" value="<?php echo $row['score'] ?>"></td>
+        </tr>
+
+        <input type="text" name="id" value="<?php echo $row['id'] ?>" hidden>
+        <tr>
+            <td colspan="2" align="center"><input type="submit" name='submit' value="提交">&nbsp;&nbsp;&nbsp;&nbsp; <input type="reset" value="取消"></td>
+
+        </tr>
+    </table>
+    <a href="li.php">返回</a>
+
+</form>
+</html>
+```
+###### update文件
+```php
+<?php
+include_once('conn.php');
+if(!isset($_POST['submit'])){
+    die("非法访问！");
+}
+
+$id=$_POST['id'];
+$name=$_POST['name'];
+$score=$_POST['score'];
+
+
+$sql = "update `user` set `name`='$name',`score`=$score where id=$id";
+
+$ret = mysqli_query($conn,$sql);
+if($ret){
+    echo "修改成功！<a href='li.php'>返回首页</a>";
+}else{
+    echo "修改失败！";
+}
+
+```
+
+#### 删除数据
+###### delete文件
+```php
+<?php
+include_once('conn.php');
+$id=$_GET['id'];
+$sql = "delete from `user` where id=$id";
+$ret = mysqli_query($conn,$sql);
+if($ret){
+    echo "删除成功！<a href='li.php'>返回首页</a>";
+}else{
+    echo "删除失败！";
+}
+```
+
+#### mysql代码
+```php
+create database student charset utf8;
+use student;
+create table user(
+id int primary key auto_increment,
+name varchar(10) not null,
+score DECIMAL not null
+);
+```
+#### index文件
+```php
+<?php
+session_start();//启动
+$user=$_SESSION['username']?:$_COOKIE['username'];
+if(isset($user) && $user=="admin"){
+    header("location:li.php");
+}else{
+    header('location:login.html');
+}
+
+```
+
+#### login.html文件
+```php
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <title>学生系统登陆</title>
+</head>
+<h1>登录页面</h1>
+<form action="login.php" method="post">
+    <table>
+        <tr>
+            <td>用户名</td><td><input type="text" name="admin" id=""></td>
+        </tr> 
+        <tr>
+            <td>密码</td><td><input type="password" name="password" id=""></td>
+        </tr>
+        <tr>
+            <td> </td><td><input type="checkbox" name="auto" value="yes">7天内自动登录</td>
+        </tr>
+        <tr>
+            <td><input type="submit" value="登录"></td>
+        </tr>
+    </table>
+    
+</form>
+</html>
+```
+#### login.php文件
+```php
+<?php
+session_start();
+$username="admin";
+$password="123456";
+
+if($username==$_POST["admin"] && $password==$_POST["password"]){
+    $_SESSION['username']=$username;
+    error_reporting(E_ALL^E_NOTICE);
+    if($_POST['auto']=='yes'){
+        setcookie('username',"admin",time()+60*60*24*7);
+    }
+    header("location:li.php");
+}else{
+    die("登录失败");
+}
+```
+
+#### loginout.php文件
+```php
+<?php
+session_start();
+unset($_SESSION['username']);
+setcookie('username','',time()-1);
+echo "注销成功";
+```
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