diff --git "a/\346\235\250\347\201\277/20220529.md" "b/\346\235\250\347\201\277/20220529.md"
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@@ -0,0 +1,247 @@
+ ```mysql
+ CREATE DATABASE student CHARSET utf8;
+ use student;
+ CREATE table user(
+ id int PRIMARY key auto_increment,
+ name VARCHAR(20) not null,
+ score DECIMAL(5,2) not null
+ );
+ INSERT into user VALUES (1,"陈小龙",98.5),(2,"吴大虫",75.5),(3,"陈得胜",66);
+ ```
+
+```php
+<?php
+error_reporting(E_ALL ^ E_WARNING);
+$conn=mysqli_connect("127.0.0.1","root","123456","student");
+mysqli_query($conn,'set names utf8');
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <title>学生管理系统登录界面</title>
+</head>
+<body>
+<h1>学生管理系统登录界面</h1>
+<form action="login.php" method="post">
+    <table border="0" cellpadding="" cellspacing="">
+        <tr>
+            <td>用户名:</td><td><input type="text" name="username" ></td>
+        </tr>
+        <tr>
+            <td>密码:</td><td><input type="password" name="password" ></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>
+</body>
+</html>
+<?php
+session_start();
+$username = 'admin';
+$password = '123456';
+if($_POST['username']==$username && $_POST['password']==$password){
+    echo "登录成功！";
+    $_SESSION['username']=$username;
+    echo "<a href ='index.php'>返回首页</a>";
+}else{
+    echo "登录失败！<a href='login.html'>请重新登录</a>";
+}
+
+<?php
+
+session_start();
+unset($_SESSION['username']);
+setcookie('username','',time()-1);
+echo "注销成功";
+
+<?php
+session_start();
+if (!isset($_SESSION['username'])){
+
+    echo "登录失败！<br>";
+    echo "返回登录界面<br><a href='login.html'>请重新登录</a>";
+    die();
+}
+include_once('conn.php');
+$sql = "select * from `user` order by id";
+$result = mysqli_query($conn,$sql);
+?>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>
+        学生管理系统
+    </title>
+    <script>
+        function del(){
+            if(!window.confirm("确定要删除吗？")){
+                return false;
+            }
+        }
+    </script>
+</head>
+<body>
+<h1>学生管理系统-首页</h1>
+<table border="1" width="300">
+    <tr>
+        <th>编号</th>
+        <th>姓名</th>
+        <th>成绩</th>
+        <th>操作</th>
+    </tr>
+    <?php
+
+    if(!mysqli_num_rows($result)) {//mysqli_num_rows() 
+        echo "<tr align='center'><td colspan='4'>暂无数据！</td></tr>";
+    }else {
+    while ($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 $row['id'] ?>" onclick="return del();">删除</a></td>
+    </tr>
+
+
+
+   <?php
+    }
+    }
+    ?>
+</table>
+<a href="add.php">添加数据</a>
+</body>
+</html>
+//add.php
+<?php
+?>
+<html>
+<head>
+    <title>添加数据</title>
+</head>
+<h1>添加数据</h1>
+<form action="save.php" method="post">
+    <table border="1" width="300">
+        <tr>
+            <th>姓名</th><td><input type="text" name="name"></td>
+        </tr>
+        <tr>
+            <th>成绩</th><td><input type="text" name="score"></td>
+        </tr>
+        <tr>
+            <td colspan="2" align="center"><input type="submit" name='submit' value="提交">&nbsp;&nbsp;&nbsp;&nbsp;
+                <input type="reset" value="取消"></td>
+
+        </tr>
+    </table>
+    <a href="index.php">返回</a>
+
+</form>
+</html>
+//edit.php
+<?php
+include_once ("./conn.php");
+if(!isset($_GET['id'])){
+    die("非法访问！");
+}
+$id=$_GET['id'];
+
+$sql = "select * from `user` where `id`=$id";
+$result = mysqli_query($conn,$sql);
+$row = mysqli_fetch_assoc($result);
+?>
+<html>
+<head>
+    <title>修改数据</title>
+
+</head>
+<h1>修改数据</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 $row['id'] ?>" hidden>
+        <tr>
+            <td colspan="2" align="center"><input type="submit" name='submit' value="提交">&nbsp;&nbsp;&nbsp;&nbsp;
+                <input type="reset" value="取消"></td>
+
+        </tr>
+    </table>
+    <a href="index.php">返回</a>
+
+</form>
+</html>
+
+<?php
+/**
+ * 接收表单数据。并提交到数据库
+ */
+
+include_once('conn.php');
+
+if(!isset($_POST['submit'])){
+    die("非法访问！");
+}
+$id=$_POST['id'];//编号
+$name=$_POST['name'];// 姓名
+$score=$_POST['score'];// 成绩
+
+$sql = "update `user` set `name`='$name',score=$score where id=$id";
+$ret = mysqli_query($conn,$sql);
+if($ret){
+    echo "修改成功！<a href='./index.php'>返回首页</a>";
+}else{
+    echo "修改失败！";
+}
+
+<?php
+/**
+ * 接收表单数据。并提交到数据库
+ */
+
+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='./index.php'>返回首页</a>";
+}else{
+    echo "删除失败！";
+}
+<?php
+/**
+ * 接收表单数据。并提交到数据库
+ */
+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)";
+
+$ret = mysqli_query($conn,$sql);
+if($ret){
+    echo "添加成功！<a href='./index.php'>返回首页</a>";
+}else{
+    echo "添加失败！";
+}
+```
+
