Question

I’m pretty new at Django and wondering what is the difference between defining model vs queryset in a generic view like ListView. Here’s my code example in my urls.py file for the project:

urlpatterns = patterns('',
    url(r'^$', ListView.as_view(
    model=Person,
    context_object_name='people',
    template_name='index.html', 
    )),
)

I’ve also used the same this:

urlpatterns = patterns('',
    url(r'^$', ListView.as_view(
    queryset=Person.objects.all,
    context_object_name='people',
    template_name='index.html', 
    )),
)

And received the same result on my view. I’m assuming there are different things you can do with a queryset?

Answer 1

Using model=Person or queryset=Person.objects.all give the same result.

Let’s look at the code. A ListView has the following method:

def get_queryset(self):
    """
    Get the list of items for this view. This must be an interable, and may
    be a queryset (in which qs-specific behavior will be enabled).
    """
    if self.queryset is not None:
        queryset = self.queryset
        if hasattr(queryset, '_clone'):
            queryset = queryset._clone()
    elif self.model is not None:
        queryset = self.model._default_manager.all()
    else:
        raise ImproperlyConfigured(u"'%s' must define 'queryset' or 'model'"
                                   % self.__class__.__name__)
    return queryset

As you can see, it first looks for self.queryset and, if that does not exist, for self.model. So there are two possibilities to specify a list: you can provide a queryset yourself or you can specify a model class (in which case Django will call the all() method of the default manager, which is objects).

I’m assuming there are different things you can do with a queryset?

Yes. If you specify a model, then you get all instances by default. But if you specify a queryset, you can also call other methods of a model manager, such as Person.objects.children() which could return only persons with age <= 12.