/tests/modeltests/custom_managers/models.py
Python | 59 lines | 33 code | 13 blank | 13 comment | 0 complexity | 7dea533fbcf0d098ddf5d8ab58baaef8 MD5 | raw file
Possible License(s): BSD-3-Clause
- """
- 23. Giving models a custom manager
- You can use a custom ``Manager`` in a particular model by extending the base
- ``Manager`` class and instantiating your custom ``Manager`` in your model.
- There are two reasons you might want to customize a ``Manager``: to add extra
- ``Manager`` methods, and/or to modify the initial ``QuerySet`` the ``Manager``
- returns.
- """
- from django.db import models
- # An example of a custom manager called "objects".
- class PersonManager(models.Manager):
- def get_fun_people(self):
- return self.filter(fun=True)
- class Person(models.Model):
- first_name = models.CharField(max_length=30)
- last_name = models.CharField(max_length=30)
- fun = models.BooleanField()
- objects = PersonManager()
- def __unicode__(self):
- return u"%s %s" % (self.first_name, self.last_name)
- # An example of a custom manager that sets get_query_set().
- class PublishedBookManager(models.Manager):
- def get_query_set(self):
- return super(PublishedBookManager, self).get_query_set().filter(is_published=True)
- class Book(models.Model):
- title = models.CharField(max_length=50)
- author = models.CharField(max_length=30)
- is_published = models.BooleanField()
- published_objects = PublishedBookManager()
- authors = models.ManyToManyField(Person, related_name='books')
- def __unicode__(self):
- return self.title
- # An example of providing multiple custom managers.
- class FastCarManager(models.Manager):
- def get_query_set(self):
- return super(FastCarManager, self).get_query_set().filter(top_speed__gt=150)
- class Car(models.Model):
- name = models.CharField(max_length=10)
- mileage = models.IntegerField()
- top_speed = models.IntegerField(help_text="In miles per hour.")
- cars = models.Manager()
- fast_cars = FastCarManager()
- def __unicode__(self):
- return self.name