87 lines
2.4 KiB
Python
87 lines
2.4 KiB
Python
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"""
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23. Giving models a custom manager
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"""
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from django.db import models
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# An example of providing a custom manager called "objects".
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class PersonManager(models.Manager):
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def get_fun_people(self):
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return self.get_list(fun__exact=True)
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class Person(models.Model):
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first_name = models.CharField(maxlength=30)
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last_name = models.CharField(maxlength=30)
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fun = models.BooleanField()
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objects = PersonManager()
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def __repr__(self):
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return "%s %s" % (self.first_name, self.last_name)
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# An example of providing a custom manager that isn't called "objects".
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class PublishedBookManager(models.Manager):
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def get_list(self, **kwargs):
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kwargs['is_published__exact'] = True
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return models.Manager.get_list(self, **kwargs)
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class Book(models.Model):
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title = models.CharField(maxlength=50)
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author = models.CharField(maxlength=30)
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is_published = models.BooleanField()
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published_objects = PublishedBookManager()
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def __repr__(self):
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return self.title
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# An example of providing multiple custom managers.
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class FastCarManager(models.Manager):
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def get_list(self, **kwargs):
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kwargs['top_speed__gt'] = 150
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return models.Manager.get_list(self, **kwargs)
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class Car(models.Model):
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name = models.CharField(maxlength=10)
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mileage = models.IntegerField()
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top_speed = models.IntegerField(help_text="In miles per hour.")
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cars = models.Manager()
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fast_cars = FastCarManager()
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def __repr__(self):
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return self.name
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API_TESTS = """
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>>> p1 = Person(first_name='Bugs', last_name='Bunny', fun=True)
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>>> p1.save()
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>>> p2 = Person(first_name='Droopy', last_name='Dog', fun=False)
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>>> p2.save()
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>>> Person.objects.get_fun_people()
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[Bugs Bunny]
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>>> b1 = Book(title='How to program', author='Rodney Dangerfield', is_published=True)
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>>> b1.save()
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>>> b2 = Book(title='How to be smart', author='Albert Einstein', is_published=False)
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>>> b2.save()
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# The default manager, "objects", doesn't exist,
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# because a custom one was provided.
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>>> Book.objects
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Traceback (most recent call last):
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...
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AttributeError: type object 'Book' has no attribute 'objects'
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>>> Book.published_objects.get_list()
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[How to program]
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>>> c1 = Car(name='Corvette', mileage=21, top_speed=180)
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>>> c1.save()
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>>> c2 = Car(name='Neon', mileage=31, top_speed=100)
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>>> c2.save()
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>>> Car.cars.get_list(order_by=('name',))
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[Corvette, Neon]
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>>> Car.fast_cars.get_list()
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[Corvette]
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"""
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