处理django模型中的重复项

Question

This is my location object

class Location(models.Model):
    country = models.CharField(max_length=255)
    city = models.CharField(max_length=255, unique=True)
    latitude = models.CharField(max_length=255)
    longitude = models.CharField(max_length=255)

    class Meta:
        unique_together = ('country', 'city')

This is the view in which I create a location,

class LocationView(views.APIView):
    def post(self, request):
        serializer = LocationSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        else:
            Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

Now while saving the new location if the database throws duplication error, then I want to not write the new value but fetch the already existent data and return it as a success response message. In sense I want to add another else clause. I'm not sure how to do this in django. Any help appreciated.

Answer 1

what about get_or_create() ?

see here for reference how it works https://docs.djangoproject.com/en/2.0/ref/models/querysets/#get-or-create

be aware of possibility for using created to distinguish either it was just get or create new case:

obj, created = Person.objects.get_or_create(
    first_name='John',
    last_name='Lennon',
    defaults={'birthday': date(1940, 10, 9)},
)