django-qmixin is a reusable Django application for extending managers and the
querysets they produce.
A mixin is a subclass of
djqmixin.QMixin which defines some related methods
that operate on a
Manager instance. Mixins can be ‘mixed in’ to
a manager class, and their methods will be made available on all instances of
that class (whether on the model itself or via a relation), as well as the
QuerySet instances it produces.
What this achieves is the ability to add queryset-level functionality to your model with the minimum amount of work possible.
Well, not quite.
Manager.include() doesn't monkey patch, and there's very
little magic involved. Overall, there are only 38 lines of code in this library,
and they're all quite heavily commented, so you can find out for yourself if you
easy_install django-qmixin # OR pip install django-qmixin
The only other thing you'll need is Django itself; this library has been tested on versions 1.0 and 1.1.
Basic usage is as follows:
from django.db import models from djqmixin import Manager, QMixin class AgeMixin(QMixin): def minors(self): return self.filter(age__lt=18) def adults(self): return self.filter(age__gte=18) class Group(models.Model): pass class Person(models.Model): GENDERS = dict(m='Male', f='Female', u='Unspecified').items() group = models.ForeignKey(Group, related_name='people') gender = models.CharField(max_length=1, choices=GENDERS) age = models.PositiveIntegerField() objects = Manager.include(AgeMixin)() # The `minors()` and `adults()` methods will be available on the manager: assert isinstance(Person.objects.minors(), models.query.QuerySet) # They'll be available on subsequent querysets: assert isinstance(Person.objects.filter(gender='m').minors(), models.query.QuerySet) # They'll also be available on relations, if they were mixed in to the # default manager for that model: group = Group.objects.all() assert isinstance(group.people.minors(), models.query.QuerySet)
A test project is located in
test/example/; consult this for a more
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