php数据库如何实现用户注册 php数据库典型业务逻辑的开发

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    username VARCHAR(50) UNIQUE NOT NULL,
    email VARCHAR(100) UNIQUE NOT NULL,
    password VARCHAR(255) NOT NULL,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

<form method="POST" action="do_register.php">
    用户名: <input type="text" name="username" required><br>
    邮箱: <input type="email" name="email" required><br>
    密码: <input type="password" name="password" required><br>
    <button type="submit">注册</button>
</form>

<?php
$host = 'localhost';
$db   = 'test_db';
$user = 'root';
$pass = '';
$charset = 'utf8mb4';

$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$options = [
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    PDO::ATTR_EMULATE_PREPARES   => false,
];

try {
    $pdo = new PDO($dsn, $user, $pass, $options);
} catch (&#36;e) {
    die('数据库连接失败：' . &#36;e->getMessage());
}

// 接收并过滤输入
&#36;username = trim(&#36;_POST['username']);
&#36;email = trim(&#36;_POST['email']);
&#36;password = &#36;_POST['password'];

// 基础验证
if (empty(&#36;username) || empty(&#36;email) || empty(&#36;password)) {
    die('所有字段均为必填');
}

if (!filter_var(&#36;email, FILTER_VALIDATE_EMAIL)) {
    die('邮箱格式不正确');
}

if (strlen(&#36;password) < 6) {
    die('密码至少6位');
}

// 检查用户名或邮箱是否已存在
&#36;stmt = &#36;pdo->prepare("SELECT id FROM users WHERE username = ? OR email = ?");
&#36;stmt->execute([&#36;username, &#36;email]);

if (&#36;stmt->rowCount() > 0) {
    die('用户名或邮箱已被注册');
}

// 加密密码
&#36;hashedPassword = password_hash(&#36;password, PASSWORD_DEFAULT);

// 插入新用户
&#36;stmt = &#36;pdo->prepare("INSERT INTO users (username, email, password) VALUES (?, ?, ?)");
&#36;result = &#36;stmt->execute([&#36;username, &#36;email, &#36;hashedPassword]);

if (&#36;result) {
    echo '注册成功！';
} else {
    echo '注册失败，请重试。';
}
?>