php中的座位预订系统

CREATE TABLE seats (
    id INT AUTO_INCREMENT PRIMARY KEY,
    row CHAR(1),
    number INT,
    status ENUM('available', 'reserved') DEFAULT 'available'
);

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

$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$pdo = new PDO($dsn, $user, $pass);

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $seatId = $_POST['seat_id'];
    $stmt = $pdo->prepare("UPDATE seats SET status = 'reserved' WHERE id = ?");
    $stmt->execute([$seatId]);
}

$stmt = $pdo->query("SELECT * FROM seats WHERE status = 'available'");
$seats = $stmt->fetchAll();
?>

<form method="POST">
    <select name="seat_id">
        <?php foreach ($seats as $seat): ?>
            <option value="<?= $seat['id'] ?>"><?= $seat['row'] . $seat['number'] ?></option>
        <?php endforeach; ?>
    </select>
    <button type="submit">Reserve</button>
</form>