Updating to non-standard database in DRF - django

Question

Using Django Rest Framework, how to execute update/PUT calls to a non-standard database?
In my Django project I'm using a separate database for the application data:
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
},
'bookstore': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': os.path.join(BASE_DIR, 'bookstore.sqlite3'),
}
}
I use the ModelSerializer and ModelViewSet to automatically create the API for me. I loop over the models to automatically generate all the Serializers and ViewSets (quite a big number of tables), the generated classes end up looking like this:
ModelSerializer:
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = '__all__'
ModelViewSet:
class BookViewSet(viewsets.ModelViewSet):
queryset = Book.objects.using('bookstore').all()
serializer_class = BookSerializer
I needed to add the using('bookstore') here to make this work.
Reading (GET) works fine. When I try to do a PUT update, I get a no such table: book Sqlite error.
It seems like the update isn't routed to the bookstore database.
For completeness, I use these loops to generate the ModelSerializer and ModelViewSets from the models:
ModelSerializer, generator:
models = dict(apps.all_models['api'])
for name, model in models.items():
class_name = name[:1].upper() + name[1:] + 'Serializer'
Meta = type('Meta', (object, ), {'model': model, 'fields': '__all__'})
print(class_name)
globals()[class_name] = type(class_name, (serializers.ModelSerializer,), {'Meta':Meta, })
ModelViewSet, generator:
models = dict(apps.all_models['api'])
for name, model in models.items():
capitalized_class_name = name[:1].upper() + name[1:]
viewset_class_name = capitalized_class_name + 'ViewSet'
serializer_class_name = capitalized_class_name + 'Serializer'
globals()[viewset_class_name] = type(viewset_class_name, (viewsets.ModelViewSet,), {'queryset': model.objects.using('bookstore').all(), 'serializer_class': globals()[serializer_class_name],'filter_backends': [filters.OrderingFilter], })