mysql数据如何更新_PHP中更新mysql数据的正确方式

try {
    $pdo = new PDO("mysql:host=localhost;dbname=testdb", "username", "password");
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $sql = "UPDATE users SET name = ?, email = ? WHERE id = ?";
    $stmt = $pdo->prepare($sql);
    $stmt->execute(['张三', 'zhangsan@example.com', 1]);

    echo "数据更新成功";
} catch (PDOException $e) {
    echo "更新失败: " . $e->getMessage();
}

$mysqli = new mysqli("localhost", "username", "password", "testdb");

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

$sql = "UPDATE users SET name = ?, email = ? WHERE id = ?";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("ssi", $name, $email, $id);

$name = '李四';
$email = 'lisi@example.com';
$id = 2;

$stmt->execute();

if ($stmt->affected_rows > 0) {
    echo "记录已更新";
} else {
    echo "未更新任何记录";
}

$stmt->close();
$mysqli->close();

// ❌ 危险！不要这样做
$id = $_POST['id'];
$name = $_POST['name'];
$sql = "UPDATE users SET name = '$name' WHERE id = $id";
$mysqli->query($sql); // 可能被注入攻击