See this snippet on Djangosnippets: http://djangosnippets.org/snippets/734/ Instead of putting your custom methods in a manager, you subclass the queryset itself. It’s very easy and works perfectly. The only issue I’ve had is with model inheritance, you always have to define the manager in model subclasses (just: “objects = QuerySetManager()” in the subclass), even though they … Read more
You have created a new user model but you have not yet specified a manager for that model. If you’re not yet familiar with managers in Django I suggest reading the documentation on that first. As the Django 1.5 say (source): You should also define a custom manager for your User model. If your User … Read more
One way to handle this would be to create a new method instead of redefining get_query_set. Something along the lines of: class UserContactManager(models.Manager): def for_user(self, user): return super(UserContactManager, self).get_query_set().filter(creator=user) class UserContact(models.Model): […] objects = UserContactManager() This allows your view to look like this: contacts = Contact.objects.for_user(request.user) This should help keep your view simple, and because … Read more
For completeness of the topic, Django 1.7 (finally) supports using a custom reverse manager, so you can do something like that (just copying from the django docs): from django.db import models class Entry(models.Model): objects = models.Manager() # Default Manager entries = EntryManager() # Custom Manager b = Blog.objects.get(id=1) b.entry_set(manager=”entries”).all()
Yes, that is what prefetch_related() is for. It will require an additional query, but the idea is that it will get all of the related information at once, instead of once per Person. In your case: qs.select_related(‘position__report_to’) .prefetch_related(‘position__report_to__person_set’) should require two queries, regardless of the number of Persons in the original query set. Compare this … Read more
The method all() on a manager just delegates to get_queryset(), as you can see in the Django source code: def all(self): return self.get_queryset() So it’s just a way to get the QuerySet from the Manager. This can be handy to ensure that you’re dealing with a QuerySet and not a Manager, because MyModel.objects returns a … Read more
The Django 1.7 released a new and simple way to create combined queryset and model manager: class InquiryQuerySet(models.QuerySet): def for_user(self, user): return self.filter( Q(assigned_to_user=user) | Q(assigned_to_group__in=user.groups.all()) ) class Inquiry(models.Model): objects = InqueryQuerySet.as_manager() See Creating Manager with QuerySet methods for more details.
Mainly to allow for easy composition of queries. Generally if you want to be able perform some operation on an existing queryset in a chain of queryset calls you can use a QuerySet. For example, say you have an Image model that has a width, height fields: class Image(models.Model): width = … # Width in … Read more
The error in question is caused when you try to access the Manager of a model through an instance of the model. You have used lower case class names. This makes it hard to say if the error is caused by an instance accessing the Manager or not. Since other scenarios that can cause this … Read more
EDIT: This answer applies if you want to change settings for a small number of specific tests. Since Django 1.4, there are ways to override settings during tests: https://docs.djangoproject.com/en/stable/topics/testing/tools/#overriding-settings TestCase will have a self.settings context manager, and there will also be an @override_settings decorator that can be applied to either a test method or a … Read more