Django DoesNotExist

Question

我在嘗試計算「DoesNotExist錯誤」時遇到了問題，我試圖找到正確的方式來管理無回答結果，但是我繼續在「DoesNotExist」或「Object hast not Attribute DoestNotExists」

from django.http import HttpResponse 
from django.contrib.sites.models import Site 
from django.utils import simplejson 

from vehicles.models import * 
from gpstracking.models import * 


def request_statuses(request): 

    data = [] 
    vehicles = Vehicle.objects.filter() 
    Vehicle.vehicledevice_ 
    for vehicle in vehicles: 
     try: 
      vehicledevice = vehicle.vehicledevice_set.get(is_joined__exact = True) 
      imei = vehicledevice.device.imei 
      try: 
       lastposition = vehicledevice.device.devicetrack_set.latest('date_time_process') 
       altitude = lastposition.altitude 
       latitude = lastposition.latitude 
       longitude = lastposition.longitude 
       date_time_process = lastposition.date_time_process.strftime("%Y-%m-%d %H:%M:%S"), 
       date_time_created = lastposition.created.strftime("%Y-%m-%d %H:%M:%S") 
      except Vehicle.vehicledevice.device.DoesNotExist: 
       lastposition = None 
       altitude = None 
       latitude = None 
       longitude = None 
       date_time_process = None 
       date_time_created = None 
     except Vehicle.DoesNotExist: 
      vehicledevice = None 
      imei = '' 

     item = [ 
       vehicle.vehicle_type.name, 
       imei, 
       altitude, 
       "Lat %s Lng %s" % (latitude, longitude), 
       date_time_process, 
       date_time_created, 
       '', 
       '' 
       ] 
     data.append(item) 
    statuses = { 
       "sEcho": 1, 
       "iTotalRecords": vehicles.count(), 
       "iTotalDisplayRecords": vehicles.count(), 
       "aaData": data 
       } 
    json = simplejson.dumps(statuses) 
    return HttpResponse(json, mimetype='application/json') 

Answer 1

我發現使用ObjectDoesNotExist在這條路上

from django.core.exceptions import ObjectDoesNotExist 
...... 

try: 
    # try something 
except ObjectDoesNotExist: 
    # do something 

在此之後，解決這個問題，我的代碼工作，因爲我需要

感謝任何方式，您的文章幫我解決問題

Answer 2

此行

except Vehicle.vehicledevice.device.DoesNotExist 

意味着尋找設備例如爲DoesNotExist例外，但有沒有，因爲它是在一流水平，你想要的東西像

except Device.DoesNotExist