php数据库登录注册

<?php
// 数据库连接
$servername = "localhost";
$username = "dbuser";
$password = "dbpass";
$dbname = "myDB";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 注册
if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['register'])) {
    $username = $_POST['username'];
    $password = password_hash($_POST['password'], PASSWORD_DEFAULT);

    $sql = "INSERT INTO users (username, password) VALUES ('$username', '$password')";

    if ($conn->query($sql) === TRUE) {
        echo "新记录插入成功";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}

// 登录
if ($_SERVER["REQUEST_METHOD"] == "POST" && isset($_POST['login'])) {
    $username = $_POST['username'];
    $password = $_POST['password'];

    $sql = "SELECT * FROM users WHERE username = '$username'";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        $row = $result->fetch_assoc();
        if (password_verify($password, $row["password"])) {
            echo "登录成功";
        } else {
            echo "密码错误";
        }
    } else {
        echo "用户名不存在";
    }
}
$conn->close();
?>

<!-- 登录注册表单 -->
<form method="post">
    Username: <input type="text" name="username"><br>
    Password: <input type="password" name="password"><br>
    <input type="submit" name="register" value="Register">
    <input type="submit" name="login" value="Login">
</form>