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 QuerySet
or 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
like.
The usual:
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()[0]
assert isinstance(group.people.minors(), models.query.QuerySet)
A test project is located in test/example/
; consult this for a more
comprehensive example.
This is free and unencumbered software released into the public domain.
Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means.
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