PHP development to build an enterprise resource planning (ERP) system with user management functions

CREATE TABLE `users` (
  `id` INT(11) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
  `username` VARCHAR(50) NOT NULL,
  `password` VARCHAR(255) NOT NULL,
  `role_id` INT(11) UNSIGNED,
  `created_at` DATETIME DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE `roles` (
  `id` INT(11) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
  `name` VARCHAR(50) NOT NULL
);

<?php
// index.php

include 'db.php';

// 查询数据库，获取所有用户
$query = "SELECT users.*, roles.name as role_name FROM users LEFT JOIN roles ON users.role_id = roles.id";
$result = mysqli_query($conn, $query);

// 获取用户列表
$users = [];
while ($row = mysqli_fetch_assoc($result)) {
    $users[] = $row;
}

// 显示用户列表
foreach ($users as $user) {
    echo "ID: " . $user['id'] . "<br>";
    echo "用户名: " . $user['username'] . "<br>";
    echo "角色: " . $user['role_name'] . "<br>";
    echo "创建时间: " . $user['created_at'] . "<br>";
    echo "<a href='edit.php?id=" . $user['id'] . "'>编辑</a> ";
    echo "<a href='delete.php?id=" . $user['id'] . "'>删除</a><br><br>";
}

// 添加新用户按钮
echo "<a href='add.php'>添加用户</a>";

mysqli_close($conn);
?>

<?php
// add.php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    include 'db.php';
  
    // 获取表单数据
    $username = $_POST['username'];
    $password = $_POST['password'];
    $role_id = $_POST['role_id'];
  
    // 插入新用户数据到数据库
    $query = "INSERT INTO users (username, password, role_id) VALUES ('$username', '$password', $role_id)";
    mysqli_query($conn, $query);
  
    mysqli_close($conn);
    header('Location: index.php');
    exit;
}
?>

<form method="POST" action="">
  <label for="username">用户名</label>
  <input type="text" name="username" id="username" required><br>
  
  <label for="password">密码</label>
  <input type="password" name="password" id="password" required><br>
  
  <label for="role_id">角色</label>
  <select name="role_id" id="role_id">
    <option value="1">管理员</option>
    <option value="2">普通用户</option>
  </select><br>
  
  <input type="submit" value="添加用户">
</form>

<?php
// edit.php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    include 'db.php';
  
    // 获取表单数据
    $id = $_POST['id'];
    $username = $_POST['username'];
    $password = $_POST['password'];
    $role_id = $_POST['role_id'];
  
    // 更新用户数据
    $query = "UPDATE users SET username='$username', password='$password', role_id=$role_id WHERE id=$id";
    mysqli_query($conn, $query);
  
    mysqli_close($conn);
    header('Location: index.php');
    exit;
}

include 'db.php';

// 获取用户ID
$id = $_GET['id'];

// 查询数据库，获取用户信息
$query = "SELECT * FROM users WHERE id=$id";
$result = mysqli_query($conn, $query);
$user = mysqli_fetch_assoc($result);

mysqli_close($conn);
?>

<form method="POST" action="">
  <!-- 显示原来的用户信息 -->
  <input type="hidden" name="id" value="<?php echo $user['id']; ?>">
  
  <label for="username">用户名</label>
  <input type="text" name="username" id="username" value="<?php echo $user['username']; ?>" required><br>
  
  <label for="password">密码</label>
  <input type="password" name="password" id="password" value="<?php echo $user['password']; ?>" required><br>
  
  <label for="role_id">角色</label>
  <select name="role_id" id="role_id">
    <option value="1" <?php if ($user['role_id'] === 1) echo 'selected'; ?>>管理员</option>
    <option value="2" <?php if ($user['role_id'] === 2) echo 'selected'; ?>>普通用户</option>
  </select><br>
  
  <input type="submit" value="保存修改">
</form>