Laravel中使用数据库自动事务

try{

DB::transaction(function () use ($orderParser, $json, $e_poi) {
   $order = $orderParser->parse($json);
   event(new OrderPushed($order, Carbon::now(), $e_poi['poi_id'], $json['order']['orderId'], $json));
});

}catch(\Illuminate\Database\QueryException $ex){

 return back() -> with(['info' => '抱歉，修改失败，请稍后重试！']);

}

return redirect('admin/buy/supplier') -> with(['info' => '修改成功']);