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36 lines
1.3 KiB
Python
36 lines
1.3 KiB
Python
"""
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Many-to-many relationships between the same two tables
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In this example, a ``Person`` can have many friends, who are also ``Person``
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objects. Friendship is a symmetrical relationship - if I am your friend, you
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are my friend. Here, ``friends`` is an example of a symmetrical
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``ManyToManyField``.
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A ``Person`` can also have many idols - but while I may idolize you, you may
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not think the same of me. Here, ``idols`` is an example of a non-symmetrical
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``ManyToManyField``. Only recursive ``ManyToManyField`` fields may be
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non-symmetrical, and they are symmetrical by default.
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This test validates that the many-to-many table is created using a mangled name
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if there is a name clash, and tests that symmetry is preserved where
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appropriate.
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"""
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from django.db import models
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class Person(models.Model):
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name = models.CharField(max_length=20)
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friends = models.ManyToManyField('self')
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colleagues = models.ManyToManyField('self', symmetrical=True, through='Colleague')
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idols = models.ManyToManyField('self', symmetrical=False, related_name='stalkers')
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def __str__(self):
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return self.name
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class Colleague(models.Model):
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first = models.ForeignKey(Person, models.CASCADE)
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second = models.ForeignKey(Person, models.CASCADE, related_name='+')
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first_meet = models.DateField()
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