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953badbea5
backwards compatible for all practical purposes. Fixed #2391, #2489, #2996, #3322, #3344, #3370, #3406, #3432, #3454, #3492, #3582, #3690, #3878, #3891, #3937, #4039, #4141, #4227, #4286, #4291, #4300, #4452, #4702 git-svn-id: http://code.djangoproject.com/svn/django/trunk@5609 bcc190cf-cafb-0310-a4f2-bffc1f526a37
60 lines
1.8 KiB
Python
60 lines
1.8 KiB
Python
"""
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25. Reverse lookups
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This demonstrates the reverse lookup features of the database API.
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"""
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from django.db import models
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class User(models.Model):
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name = models.CharField(maxlength=200)
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def __unicode__(self):
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return self.name
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class Poll(models.Model):
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question = models.CharField(maxlength=200)
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creator = models.ForeignKey(User)
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def __unicode__(self):
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return self.question
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class Choice(models.Model):
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name = models.CharField(maxlength=100)
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poll = models.ForeignKey(Poll, related_name="poll_choice")
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related_poll = models.ForeignKey(Poll, related_name="related_choice")
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def __unicode__(self):
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return self.name
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__test__ = {'API_TESTS':"""
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>>> john = User(name="John Doe")
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>>> john.save()
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>>> jim = User(name="Jim Bo")
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>>> jim.save()
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>>> first_poll = Poll(question="What's the first question?", creator=john)
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>>> first_poll.save()
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>>> second_poll = Poll(question="What's the second question?", creator=jim)
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>>> second_poll.save()
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>>> new_choice = Choice(poll=first_poll, related_poll=second_poll, name="This is the answer.")
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>>> new_choice.save()
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>>> # Reverse lookups by field name:
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>>> User.objects.get(poll__question__exact="What's the first question?")
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<User: John Doe>
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>>> User.objects.get(poll__question__exact="What's the second question?")
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<User: Jim Bo>
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>>> # Reverse lookups by related_name:
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>>> Poll.objects.get(poll_choice__name__exact="This is the answer.")
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<Poll: What's the first question?>
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>>> Poll.objects.get(related_choice__name__exact="This is the answer.")
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<Poll: What's the second question?>
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>>> # If a related_name is given you can't use the field name instead:
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>>> Poll.objects.get(choice__name__exact="This is the answer")
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Traceback (most recent call last):
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...
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TypeError: Cannot resolve keyword 'choice' into field. Choices are: poll_choice, related_choice, id, question, creator
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"""}
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