Django bulk update list of objects

Question

I want to create an API endpoint, where you can PUT list of objects and it will work like this:

• If the ID is specified, query that object and try to update it (if the given ID is not found, show an error)
• If no ID is present for an object, create.
• If any previous objects missing saved to the db missing from this list, delete it from the database.

What I have found and did not work that way (most of them don't work at all):

https://github.com/miki725/django-rest-framework-bulk

https://www.django-rest-framework.org/api-guide/serializers/#customizing-multiple-update

The example on django-rest site seems to do it like that, however it is not working for me.

I have a serializer:

class InventoryPropertyValuesSerializer(serializers.ModelSerializer):
    added_by = serializers.CharField(source='added_by.username', read_only=True)
    updated_by = serializers.CharField(source='updated_by.username', read_only=True)
    id = serializers.IntegerField(required=False)

    class Meta:
        model = InventoryPropertyValues
        list_serializer_class = CustomBulkListSerializer
        fields = '__all__'

ListSerializer

class CustomBulkListSerializer(serializers.ListSerializer):
    def update(self, instance, validated_data):
        # Maps for id->instance and id->data item.
        value_mapping = {value.id: value for value in instance}
        data_mapping = {item['id']: item for item in validated_data}

        # Perform creations and updates.
        ret = []
        for value_id, data in data_mapping.items():
            value = value_mapping.get(value_id, None)
            if value is None:
                ret.append(self.child.create(data))
            else:
                ret.append(self.child.update(value, data))
        # Perform deletions.
        for value_id, value in value_mapping.items():
            if value_id not in data_mapping:
                value.delete()
        return ret

If I try to run, I get this: 'QuerySet' object has no attribute 'pk'

Answer 1

It seems that drf-writable-nested does exactly what I want and described in the original post.