How to save a nested object in separate models in Django?-CodePudding

I'm trying to save a nested object into two different tables in my Django app. I'm missing something because I get validation errors from the sub Model. The data in my events is not recognized and the serializer validation fails. Do I need to modify my serializer somehow or is there something wrong with my Models?

I have these two Models:

class Plan(models.Model):
    name = models.CharField(max_length=200)

class PlanEvent(models.Model):
    plan = models.ForeignKey(Plan, on_delete=models.CASCADE)
    done = models.BooleanField()
    title = models.CharField(max_length=100, blank=True)

Then I have these serializers for my Models:

class PlanEventSerializer(serializers.ModelSerializer):
    class Meta:
        model = PlanEvent
        fields = '__all__'


class PlanSerializer(serializers.ModelSerializer):
    events = PlanEventSerializer(many=True)

    class Meta:
        model = Plan
        fields  = ('name', 'events')

    def create(self, validated_data):
        events_validated_data = validated_data.pop('events')
        plan = Plan.objects.create(**validated_data)
        plan_event_serializer = self.fields['events']
        for p in events_validated_data:
            p['plan'] = plan
        events = plan_event_serializer.create(events_validated_data)
        return plan

In my views.py I do this:

class PlanView(APIView):
    permission_classes = [AllowAny,]
    serializer_class = PlanSerializer

    def post(self, request, format=None):
        serializer = self.serializer_class(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

I try to save a Plan and the PlanEvent into their own table with this payload:

{
  "name": "some name",
  "events": [
    {
      "done": false,
      "title": "some title"
    },
    {
      "done": true,
      "title": "some title"
    }
  ]
}

This gives me an error message 400 Bad Request every time:

    {
    "events": [
        {
            "plan": [
                "This field is required."
            ]
        },
        {
            "plan": [
                "This field is required."
            ]
        }
    ]
}

CodePudding user response：

The problem was, I had a mistake in here:

 for p in events_validated_data:
     p['plan'] = plan

It was supposed to be:

 for p in events_validated_data:
     p['id'] = plan

Also had to exclude the foreign key field from the serializer as Yery cs suggested.

CodePudding user response：

It seems, you need to pass plan primary key,not plan object in PlanSerializer.

for p in events_validated_data:
            p['plan'] = plan.id