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63 lines
1.8 KiB
63 lines
1.8 KiB
from django.db import models |
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# No related name is needed here, since symmetrical relations are not |
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# explicitly reversible. |
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class SelfRefer(models.Model): |
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name = models.CharField(max_length=10) |
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references = models.ManyToManyField('self') |
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related = models.ManyToManyField('self') |
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def __unicode__(self): |
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return self.name |
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class Tag(models.Model): |
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name = models.CharField(max_length=10) |
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def __unicode__(self): |
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return self.name |
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# A related_name is required on one of the ManyToManyField entries here because |
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# they are both addressable as reverse relations from Tag. |
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class Entry(models.Model): |
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name = models.CharField(max_length=10) |
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topics = models.ManyToManyField(Tag) |
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related = models.ManyToManyField(Tag, related_name="similar") |
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def __unicode__(self): |
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return self.name |
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__test__ = {"regressions": """ |
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# Multiple m2m references to the same model or a different model must be |
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# distinguished when accessing the relations through an instance attribute. |
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>>> s1 = SelfRefer.objects.create(name='s1') |
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>>> s2 = SelfRefer.objects.create(name='s2') |
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>>> s3 = SelfRefer.objects.create(name='s3') |
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>>> s1.references.add(s2) |
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>>> s1.related.add(s3) |
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>>> e1 = Entry.objects.create(name='e1') |
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>>> t1 = Tag.objects.create(name='t1') |
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>>> t2 = Tag.objects.create(name='t2') |
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>>> e1.topics.add(t1) |
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>>> e1.related.add(t2) |
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>>> s1.references.all() |
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[<SelfRefer: s2>] |
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>>> s1.related.all() |
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[<SelfRefer: s3>] |
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>>> e1.topics.all() |
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[<Tag: t1>] |
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>>> e1.related.all() |
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[<Tag: t2>] |
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# The secret internal related names for self-referential many-to-many fields |
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# shouldn't appear in the list when an error is made. |
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>>> SelfRefer.objects.filter(porcupine='fred') |
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Traceback (most recent call last): |
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... |
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FieldError: Cannot resolve keyword 'porcupine' into field. Choices are: id, name, references, related |
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""" |
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}
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