如果自动生成字母数字数据不存在，则使用php pdo创建新数据并插入

$dsn = "mysql:host=localhost;dbname=your_database_name";
$username = "your_username";
$password = "your_password";

try {
    $pdo = new PDO($dsn, $username, $password);
} catch (PDOException $e) {
    die("Database connection failed: " . $e->getMessage());
}

$data = generateRandomData(); // 生成字母数字数据的函数

$stmt = $pdo->prepare("INSERT INTO your_table_name (column1, column2) VALUES (:value1, :value2)");
$stmt->bindParam(':value1', $data['value1']);
$stmt->bindParam(':value2', $data['value2']);

if ($stmt->execute()) {
    echo "New data inserted successfully.";
} else {
    echo "Failed to insert new data.";
}