laravel检查记录存在
$user = User::where('email', '=', Input::get('email'))->first();
if ($user === null) {
// user doesn't exist
}
laravel更新,如果存在或创建
$flight = App\Flight::updateOrCreate(
['departure' => 'Oakland', 'destination' => 'San Diego'],
['price' => 99]
);