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9c52d56f6f
This is a big internal change, but mostly backwards compatible with existing code. Also adds a couple of new features. Fixed #245, #1050, #1656, #1801, #2076, #2091, #2150, #2253, #2306, #2400, #2430, #2482, #2496, #2676, #2737, #2874, #2902, #2939, #3037, #3141, #3288, #3440, #3592, #3739, #4088, #4260, #4289, #4306, #4358, #4464, #4510, #4858, #5012, #5020, #5261, #5295, #5321, #5324, #5325, #5555, #5707, #5796, #5817, #5987, #6018, #6074, #6088, #6154, #6177, #6180, #6203, #6658 git-svn-id: http://code.djangoproject.com/svn/django/trunk@7477 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(max_length=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(max_length=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(max_length=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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FieldError: Cannot resolve keyword 'choice' into field. Choices are: creator, id, poll_choice, question, related_choice
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"""}
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