How can I select an instance of django model to update the info inside that model or related models?

user_8123050 0
Viewed 27

I have basically three models.

class Users(models.Model):
    name = models.CharField(max_length=100)
    ...

class Portfolio(models.Model):
    name = models.CharField(max_length=50)
    user = models.ForeignKey(Users, on_delete=models.CASCADE, related_name='portfolio')

class BuySell(models.Model):
    portfolio = models.ForeignKey(Portfolio, on_delete=models.CASCADE, related_name='buy_sell'
    ...

Any user can have multiple portfolios and portfolios can have many buy-sell. From my viewset how can I access the portfolio instance selected by the user to add buy-sell data?

In my Viewset:

class BuySellViewSet(
        viewsets.GenericViewset, 
        mixins.ListModelMixin,
        mixins.CreateModelMixin,
        mixins.UpdateModelMixin,
        mixins.DestroyModelMixin
    ):
    
    serializer_class = BuySellSerializer
    queryset = BuySell.objects.all()
 
    def get_queryset(self):
        return self.request.user.portfolio

But when I add multiple portfolios for a single user I get the following error message:

TypeError at /api/v1/share/buy-sell/
Field 'id' expected a number but got <django.db.models.fields.related_descriptors.create_reverse_many_to_one_manager.<locals>.RelatedManager object at 0x7f857c7c6940>.

How can I select the correct portfolio instance to add buy-sell data inside that instance? Also, How'd I be adding new buy-sell records in an instance of a portfolio from my viewset?

def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        share = serializer.validated_data["share"]
        self.perform_create(serializer)
        return Response({"data": serializer.data}, status=status.HTTP_201_CREATED)
django-viewsets django-rest-framework django-models django python
1 Answers

You can filter with:

class BuySellViewSet(
        viewsets.GenericViewset, 
        mixins.ListModelMixin,
        mixins.CreateModelMixin,
        mixins.UpdateModelMixin,
        mixins.DestroyModelMixin
    ):
    
    serializer_class = BuySellSerializer
 
    def get_queryset(self):
        return BuySell.objects.filter(portfolio__user=self.request.user)
user_675790
Related