如何利用PHP开发一个简单的会员管理功能

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // 获取用户提交的注册信息
    $username = $_POST["username"];
    $password = $_POST["password"];
    $email = $_POST["email"];

    // 将会员信息插入到数据库中
    $sql = "INSERT INTO members (username, password, email) VALUES ('$username', '$password', '$email')";
    // 执行SQL语句
    // ...
}
?>
<form action="register.php" method="post">
    <input type="text" name="username" placeholder="用户名" required><br>
    <input type="password" name="password" placeholder="密码" required><br>
    <input type="email" name="email" placeholder="电子邮件" required><br>
    <input type="submit" value="注册">
</form>

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // 获取用户提交的登录信息
    $username = $_POST["username"];
    $password = $_POST["password"];

    // 在数据库中验证用户名和密码
    $sql = "SELECT * FROM members WHERE username='$username' AND password='$password'";
    // 执行SQL语句，获取结果
    // ...
}
?>
<form action="login.php" method="post">
    <input type="text" name="username" placeholder="用户名" required><br>
    <input type="password" name="password" placeholder="密码" required><br>
    <input type="submit" value="登录">
</form>

<?php
// 查询所有注册会员的信息
$sql = "SELECT * FROM members";
// 执行SQL语句，获取结果
// ...
// 遍历结果，显示会员信息
// ...
?>

<?php
// 查询所有权限信息
$sql = "SELECT * FROM roles";
// 执行SQL语句，获取结果
// ...
// 遍历结果，显示权限信息
// ...
?>

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // 获取用户提交的邮箱地址
    $email = $_POST["email"];

    // 在数据库中查找与该邮箱地址关联的会员账户
    $sql = "SELECT * FROM members WHERE email='$email'";
    // 执行SQL语句，获取结果
    // ...
    // 发送重置密码链接到该邮箱地址
    // ...
}
?>
<form action="reset_password.php" method="post">
    <input type="email" name="email" placeholder="电子邮件" required><br>
    <input type="submit" value="重置密码">
</form>