用户管理数据库（基于数据库的增删改查）

1，html页面

index.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="index.html">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">用户管理 <a class="btn btn-link btn-sm" href="edit.html">添加</a></h1>
    <table class="table table-hover">
      <thead>
        <tr>
          <th>#</th>
          <th>头像</th>
          <th>姓名</th>
          <th>性别</th>
          <th>年龄</th>
          <th class="text-center" width="140">操作</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
      </tbody>
    </table>
    <ul class="pagination justify-content-center">
      <li class="page-item"><a class="page-link" href="#">&laquo;</a></li>
      <li class="page-item"><a class="page-link" href="#">1</a></li>
      <li class="page-item"><a class="page-link" href="#">2</a></li>
      <li class="page-item"><a class="page-link" href="#">3</a></li>
      <li class="page-item"><a class="page-link" href="#">&raquo;</a></li>
    </ul>
  </main>
</body>
</html>

2，下一步，从数据库中提取数据 ( php代码）

　　①建立连接

　　②开始查询

　　③遍历结果集

<?php

    $connection=mysqli_connect('127.0.0.1','root','123456','demo03');
    if(!$connection){
        exit('连接数据库失败');
    }

    $query= mysqli_query($connection,'select * from users;');
    if(!$query){
        exit('查询失败');
    }

    while($row = mysqli_fetch_assoc($query)){
        var_dump($row);
    }

?>


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="index.html">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">用户管理 <a class="btn btn-link btn-sm" href="edit.html">添加</a></h1>
    <table class="table table-hover">
      <thead>
        <tr>
          <th>#</th>
          <th>头像</th>
          <th>姓名</th>
          <th>性别</th>
          <th>年龄</th>
          <th class="text-center" width="140">操作</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">1</th>
          <td><img src="assets/img/icon-40.png" class="rounded" alt="张三"></td>
          <td>张三</td>
          <td>♂</td>
          <td>18</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td><img src="assets/img/icon-08.png" class="rounded" alt="李四"></td>
          <td>李四</td>
          <td>♀</td>
          <td>17</td>
          <td class="text-center">
            <button class="btn btn-info btn-sm">编辑</button>
            <button class="btn btn-danger btn-sm">删除</button>
          </td>
        </tr>
      </tbody>
    </table>
    <ul class="pagination justify-content-center">
      <li class="page-item"><a class="page-link" href="#">&laquo;</a></li>
      <li class="page-item"><a class="page-link" href="#">1</a></li>
      <li class="page-item"><a class="page-link" href="#">2</a></li>
      <li class="page-item"><a class="page-link" href="#">3</a></li>
      <li class="page-item"><a class="page-link" href="#">&raquo;</a></li>
    </ul>
  </main>
</body>
</html>

3，下一步，将打印出来的数据呈现在页面上（保留 tbody 中的一个tr ,删除其他的 tr , 通过循环遍历将打印出来的数据 插入到 tr 中）

<?php

    $connection=mysqli_connect('127.0.0.1','root','123456','demo03');
    if(!$connection){
        exit('连接数据库失败');
    }

    $query= mysqli_query($connection,'select * from users;');
    if(!$query){
        exit('查询失败');
    }

    //while($row = mysqli_fetch_assoc($query)){
        //var_dump($row);
   // }

?>


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="index.html">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">用户管理 <a class="btn btn-link btn-sm" href="add.php">添加</a></h1>

    <table class="table table-hover">
      <thead>
        <tr>
          <th>#</th>
          <th>头像</th>
          <th>姓名</th>
          <th>性别</th>
          <th>年龄</th>
          <th class="text-center" width="140">操作</th>
        </tr>
      </thead>

      <tbody>
        <?php while($row=mysqli_fetch_assoc($query)):  ?>

         <tr>
             <th scope="row"><?php echo $row['id'] ?></th>
             <td><img src="<?php echo $row['avatar']; ?>" alt="<?php echo $row['name'];?>"></td>
             <td><?php echo $row['name']; ?></td>
             <td><?php echo $row['gender']== 0 ? '♂': '♀'; ?></td>
             <td><?php echo $row['birthday']; ?></td>
             <td class="text-center">
                  <button class="btn btn-info btn-sm">编辑</button>
                  <button class="btn btn-info btn-danger">删除</button>
             </td>
          </tr>

        <?php endwhile ?>


      </tbody>
    </table>
    <ul class="pagination justify-content-center">
      <li class="page-item"><a class="page-link" href="#">«</a></li>
      <li class="page-item"><a class="page-link" href="#">1</a></li>
      <li class="page-item"><a class="page-link" href="#">2</a></li>
      <li class="page-item"><a class="page-link" href="#">3</a></li>
      <li class="page-item"><a class="page-link" href="#">»</a></li>
    </ul>
  </main>
</body>
</html>

　

4,删除功能实现

　　删除是 a 标签

<?php

    $connection=mysqli_connect('127.0.0.1','root','123456','demo03');
    if(!$connection){
        exit('连接数据库失败');
    }

    $query= mysqli_query($connection,'select * from users;');
    if(!$query){
        exit('查询失败');
    }

?>


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="index.html">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">用户管理 <a class="btn btn-link btn-sm" href="add.php">添加</a></h1>

    <table class="table table-hover">
      <thead>
        <tr>
          <th>#</th>
          <th>头像</th>
          <th>姓名</th>
          <th>性别</th>
          <th>年龄</th>
          <th class="text-center" width="140">操作</th>
        </tr>
      </thead>

      <tbody>
        <?php while($row=mysqli_fetch_assoc($query)):  ?>

         <tr>
             <th scope="row"><?php echo $row['id'] ?></th>
             <td><img src="<?php echo $row['avatar']; ?>" alt="<?php echo $row['name'];?>"></td>
             <td><?php echo $row['name']; ?></td>
             <td><?php echo $row['gender']== 0 ? '♂': '♀'; ?></td>
             <td><?php echo $row['birthday']; ?></td>
             <td class="text-center">
                  <button class="btn btn-info btn-sm">编辑</button>
                  <a class="btn btn-danger btn-sm" href="delete.php? id=<?php echo $row['id']; ?>">删除</a>
             </td>
          </tr>

        <?php endwhile ?>


      </tbody>
    </table>
    <ul class="pagination justify-content-center">
      <li class="page-item"><a class="page-link" href="#">&laquo;</a></li>
      <li class="page-item"><a class="page-link" href="#">1</a></li>
      <li class="page-item"><a class="page-link" href="#">2</a></li>
      <li class="page-item"><a class="page-link" href="#">3</a></li>
      <li class="page-item"><a class="page-link" href="#">&raquo;</a></li>
    </ul>
  </main>
</body>
</html>

delete.php

<?php
    //接收要删除的数据 ID
    if(empty($_GET['id'])){
        exit('必须传入指定参数');
    }
    $id=$_GET['id'];

    $connection=mysqli_connect('127.0.0.1' , 'root' , '123456' , 'demo03');
    if(!$connection){
        exit('连接数据库失败');
    }
　　 

　　 //$query=mysqli_query($connection,'delete from users where id in (1,2,3,4););
    $query=mysqli_query($connection,'delete from users where id in ('. $id .' );'); //字符串拼接

    if(!$query){
        exit('查询失败');
    }

    $rowsAffected=mysqli_affected_rows($connection);
    if($rowsAffected <= 0){
        exit('删除失败');
    }
    header('Location: list.php');

　　　　实际开发中，删除功能没有页面

5,添加功能实现

　　添加页面add.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">添加用户</h1>
    <div class="alert alert-warning"></div>
    <form>
      <div class="form-group">
        <label for="avatar">头像</label>
        <input type="file" class="form-control" id="avatar">
      </div>
      <div class="form-group">
        <label for="name">姓名</label>
        <input type="text" class="form-control" id="name">
      </div>
      <div class="form-group">
        <label for="gender">性别</label>
        <select class="form-control" id="gender">
          <option value="-1">请选择性别</option>
          <option value="1">男</option>
          <option value="0">女</option>
        </select>
      </div>
      <div class="form-group">
        <label for="birthday">生日</label>
        <input type="date" class="form-control" id="birthday">
      </div>
      <button class="btn btn-primary">保存</button>
    </form>
  </main>
</body>
</html>

　　2,添加功能逻辑

　　　　①把 index.php中的“添加”中的 a 标签的 href 属性值改为 "add.php"

　　　　②修改 add.php中表单 form 的属性值, 以及其他表单域 加  name 属性

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">添加用户</h1>
    <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" , enctype="multipart/form-data" autocomplete="off">
      <div class="form-group">
        <label for="avatar">头像</label>
        <input type="file" class="form-control" id="avatar" name="avatar">
      </div>
      <div class="form-group">
        <label for="name">姓名</label>
        <input type="text" class="form-control" id="name" name="name">
      </div>
      <div class="form-group">
        <label for="gender">性别</label>
        <select class="form-control" id="gender" name="gender">
          <option value="-1">请选择性别</option>
          <option value="1">男</option>
          <option value="0">女</option>
        </select>
      </div>
      <div class="form-group">
        <label for="birthday">生日</label>
        <input type="date" class="form-control" id="birthday" name="birthday">
      </div>
      <button class="btn btn-primary">保存</button>
    </form>
  </main>
</body>
</html>

　　不填数据，直接点击保存按钮，可以通过浏览器的 NetWork 查看是否向服务器成功发送请求

　　③添加功能的php 脚本

　　　　Ⅰ，验证非空

　　　　Ⅱ，取值

　　　　Ⅲ，接收文件并验证

　　　　Ⅳ，保存

　　　　Ⅴ，响应

 add.php

<?php

      if($_SERVER['REQUEST_METHOD']==='POST'){
        add();
      }

      function add(){
        //验证非空
        if(empty($_POST['name'])){
            $GLOBALS['error_message']='请输入姓名';
            return;
        }
        if( !( isset($_POST['gender']) && $_POST['gender'] !== '-1' )  ){
            $GLOBALS['error_message'] = '请选择性别';
            return;
        }
        if(empty($_POST['birthday'])){
            $GLOBALS['error_message']='请输入日期';
            return;
        }

        //取值
        $name=$_POST['name'];
        $gender=$_POST['gender'];
        $birthday=$_POST['birthday'];

        //接收文件并验证
        if(empty($_FILES['avatar'])){
            $GLOBALS['error_message']='请上传头像';
            return;
        }

        $ext=pathinfo($_FILES['avatar']['name'], PATHINFO_EXTENSION); //文件的扩展名，jpg
        $target= '../target/avatar-' . uniqid() . '.' . $ext; //字符串拼接

        if(!move_uploaded_file($_FILES['avatar']['tmp_name'],$target)){
            $GLOBALS['error_message']='上传头像失败';
            return;
        }

        //保存
        $avatar=substr($target,2);
        var_dump($name);
        var_dump($gender);
        var_dump($birthday);
        var_dump($avatar);

    }

    
    
    
?>


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">添加用户</h1>
    <div class="alert alert-warning"></div>
    <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" , enctype="multipart/form-data" autocomplete="off">
      <div class="form-group">
        <label for="avatar">头像</label>
        <input type="file" class="form-control" id="avatar" name="avatar">
      </div>
      <div class="form-group">
        <label for="name">姓名</label>
        <input type="text" class="form-control" id="name" name="name">
      </div>
      <div class="form-group">
        <label for="gender">性别</label>
        <select class="form-control" id="gender" name="gender">
          <option value="-1">请选择性别</option>
          <option value="1">男</option>
          <option value="0">女</option>
        </select>
      </div>
      <div class="form-group">
        <label for="birthday">生日</label>
        <input type="date" class="form-control" id="birthday" name="birthday">
      </div>
      <button class="btn btn-primary">保存</button>
    </form>
  </main>
</body>
</html>

　　③下一步，将打印出来的插入数据放在页面中展示

<?php

      if($_SERVER['REQUEST_METHOD']==='POST'){
        add();
      }

      function add(){
        //验证非空
        if(empty($_POST['name'])){
            $GLOBALS['error_message']='请输入姓名';
            return;
        }
        if( !( isset($_POST['gender']) && $_POST['gender'] !== '-1' )  ){
            $GLOBALS['error_message'] = '请选择性别';
            return;
        }
        if(empty($_POST['birthday'])){
            $GLOBALS['error_message']='请输入日期';
            return;
        }

        //取值
        $name=$_POST['name'];
        $gender=$_POST['gender'];
        $birthday=$_POST['birthday'];

        //接收文件并验证
        if(empty($_FILES['avatar'])){
            $GLOBALS['error_message']='请上传头像';
            return;
        }

        $ext=pathinfo($_FILES['avatar']['name'], PATHINFO_EXTENSION); //文件的扩展名，jpg
        $target= '../target/avatar-' . uniqid() . '.' . $ext; //字符串拼接

        if(!move_uploaded_file($_FILES['avatar']['tmp_name'],$target)){
            $GLOBALS['error_message']='上传头像失败';
            return;
        }

        //保存
        $avatar=substr($target,2);
//        var_dump($name);
//        var_dump($gender);
//        var_dump($birthday);
//        var_dump($avatar);



      //建立连接，开始查询，响应
      $connection=mysqli_connect('127.0.0.1','root','123456','demo03');
      if(!$connection){
        //exit='连接数据库失败';
        $GLOBALS['error_message']='连接数据库失败';
        return;
      }

      $query = mysqli_query($connection, "insert into users values (null, '{$name}', {$gender}, '{$birthday}', '{$avatar}'); ");
      if(!$query){
        //exit='查询过程失败';
        $GLOBALS['error_message'] ='查询过程失败';
        return;
      }

      $rowsAffected=mysqli_affected_rows($connection);
      if($rowsAffected !==1){
        //exit='添加数据失败';
        $GLOBALS['error_message']='添加数据失败';
        return;
      }

      //响应
      header('Location: list.php');

 }


?>


<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">添加用户</h1>

    <?php if(isset($error_message)): ?>
    <div class="alert alert-warning">
        <?php echo $error_message; ?>
    </div>
    <?php endif ?>


    <div class="alert alert-warning"></div>
    <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" , enctype="multipart/form-data" autocomplete="off">
      <div class="form-group">
        <label for="avatar">头像</label>
        <input type="file" class="form-control" id="avatar" name="avatar">
      </div>
      <div class="form-group">
        <label for="name">姓名</label>
        <input type="text" class="form-control" id="name" name="name">
      </div>
      <div class="form-group">
        <label for="gender">性别</label>
        <select class="form-control" id="gender" name="gender">
          <option value="-1">请选择性别</option>
          <option value="1">男</option>
          <option value="0">女</option>
        </select>
      </div>
      <div class="form-group">
        <label for="birthday">生日</label>
        <input type="date" class="form-control" id="birthday" name="birthday">
      </div>
      <button class="btn btn-primary">保存</button>
    </form>
  </main>
</body>
</html>

 　　　　一个bug，上传本机图片作为头像无法呈现出来(应该问题出在当时设置头像路径的时候出现错误，之后添加上传的头像路径和之前的头像路径不一致)

6，编辑功能实现

　　①编辑功能的页面和添加功能的页面是一样的

　　   先将 list.php中的 “编辑”改成  a 链接 并添加 href 属性

 <a class="btn btn-info btn-sm" href="edit.php">编辑</a>

　　　然后写出编辑页面 exit.html （和add.html)页面相同

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">编辑lisa</h1>

    <?php if(isset($error_message)): ?>
    <div class="alert alert-warning">
        <?php echo $error_message; ?>
    </div>
    <?php endif ?>


    <div class="alert alert-warning"></div>
    <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" , enctype="multipart/form-data" autocomplete="off">
      <div class="form-group">
        <label for="avatar">头像</label>
        <input type="file" class="form-control" id="avatar" name="avatar">
      </div>
      <div class="form-group">
        <label for="name">姓名</label>
        <input type="text" class="form-control" id="name" name="name">
      </div>
      <div class="form-group">
        <label for="gender">性别</label>
        <select class="form-control" id="gender" name="gender">
          <option value="-1">请选择性别</option>
          <option value="1">男</option>
          <option value="0">女</option>
        </select>
      </div>
      <div class="form-group">
        <label for="birthday">生日</label>
        <input type="date" class="form-control" id="birthday" name="birthday">
      </div>
      <button class="btn btn-primary">保存</button>
    </form>
  </main>
</body>
</html>

　　　　在 edit.html中添加 php 脚本

　　　　edit.php

<?php

     //接收要修改的数据
     if(empty($_GET['id'])){
        exit('必须传入指定参数');
     }
     $id = $_GET['id'];

     //建立连接，开始查询
     $connection=mysqli_connect('127.0.0.1','root' , '123456' , 'demo03');
     if(!$connection){
        exit('连接数据库失败');
     }

     $query=mysqli_query($connection, "select * from users where id= {$id} limit 1;");//因为ID是唯一的，那么找到第一个满足条件的就不用再继续了， limit 1
     if(!$query){
        exit('查询数据失败');
     }

     $row = mysqli_fetch_assoc($query);
     if(!$row){
        exit('找不到要编辑的数据');
     }

?>

 最终编辑功能的 edit.php

<?php

     //接收要修改的数据
     if(empty($_GET['id'])){
        exit('必须传入指定参数');
     }
     $id = $_GET['id'];

     //建立连接，开始查询
     $connection=mysqli_connect('127.0.0.1','root' , '123456' , 'demo03');
     if(!$connection){
        exit('连接数据库失败');
     }

     $query=mysqli_query($connection, "select * from users where id= {$id} limit 1;");//因为ID是唯一的，那么找到第一个满足条件的就不用再继续了， limit 1
     if(!$query){
        exit('查询数据失败');
     }

     $row = mysqli_fetch_assoc($query);
     if(!$row){
        exit('找不到要编辑的数据');
     }

     if ($_SERVER['REQUEST_METHOD'] === 'POST') {
       edit();
     }


     function edit(){
        global $row;
        if(empty($_POST['name'])){
            $GLOBALS['error_message']='请输入姓名';
            return;
        }
        if(!(isset($_POST['gender']) && $_POST['gender'] !== '-1')) {
            $GLOBALS['error_message'] = '请选择性别';
            return;
        }

        if (empty($_POST['birthday'])) {
            $GLOBALS['error_message'] = '请输入日期';
            return;
         }

         //取值
          $row['name'] = $_POST['name'];
          $row['gender'] = $_POST['gender'];
          $row['birthday'] = $_POST['birthday'];

          //有上传就修改
          if (isset($_FILES['avatar']) && $_FILES['avatar']['error'] === UPLOAD_ERR_OK) {
              // 用户上传了新头像 -> 用户希望修改头像
              $ext = pathinfo($_FILES['avatar']['name'], PATHINFO_EXTENSION);
              $target = 'D:/www/site6/code/demo/target/avatar-' . uniqid() . '.' . $ext;
              if (!move_uploaded_file($_FILES['avatar']['tmp_name'], $target)) {
                $GLOBALS['error_message'] = '上传头像失败';
                return;
              }
              $row['avatar'] = substr($target, 2);
            }

            //打印出修改之后的信息
            var_dump($row);

     }

?>



<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>XXX管理系统</title>
  <link rel="stylesheet" href="assets/css/bootstrap.css">
  <link rel="stylesheet" href="assets/css/style.css">
</head>
<body>
  <nav class="navbar navbar-expand navbar-dark bg-dark fixed-top">
    <a class="navbar-brand" href="#">XXX管理系统</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="index.html">用户管理</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">商品管理</a>
      </li>
    </ul>
  </nav>
  <main class="container">
    <h1 class="heading">编辑“<?php echo $row['name']; ?>”</h1>

    <form action="<?php echo $_SERVER['PHP_SELF']; ?>?id=<?php echo $row['id']; ?>"  method="post" enctype="multipart/form-data">
      <img src="<?php echo $row['avatar]; ?>" alt="">
      <div class="form-group">
        <label for="avatar">头像</label>
        <input type="file" class="form-control" id="avatar" name="avatar"> //文件域不能设置默认值
      </div>
      <div class="form-group">
        <label for="name">姓名</label>
        <input type="text" class="form-control" id="name" name="name" value="<?php echo $row[''name]; ?>">
      </div>
      <div class="form-group">
        <label for="gender">性别</label>
        <select class="form-control" id="gender" name="gender">
          <option value="-1">请选择性别</option>
          <option value="1"<?php echo $row['gender'] === '1' ? ' selected': ''; ?>>男</option>
          <option value="0"<?php echo $row['gender'] === '0' ? ' selected': ''; ?>>女</option>
        </select>
      </div>
      <div class="form-group">
        <label for="birthday">生日</label>
        <input type="date" class="form-control" id="birthday" name="birthday" value="<?php  echo $row['birthday'];?>">
      </div>
      <button class="btn btn-primary">保存</button>
    </form>
  </main>
</body>
</html>

7，这个案例的 bug

　　①页面展示成功

　　②删除功能成功实现

　　③添加功能可以操作，但是头像上传不能呈现

　　④编辑功能有问题，报错

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原文地址：https://www.cnblogs.com/shanlu0000/p/11613157.html