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147 lines
6.5 KiB
Python
147 lines
6.5 KiB
Python
from django.db import connection
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from django.db.models import CharField, Max
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from django.db.models.functions import Lower
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from django.test import TestCase, skipUnlessDBFeature
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from django.test.utils import register_lookup
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from .models import Celebrity, Fan, Staff, StaffTag, Tag
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@skipUnlessDBFeature('can_distinct_on_fields')
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@skipUnlessDBFeature('supports_nullable_unique_constraints')
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class DistinctOnTests(TestCase):
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@classmethod
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def setUpTestData(cls):
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cls.t1 = Tag.objects.create(name='t1')
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cls.t2 = Tag.objects.create(name='t2', parent=cls.t1)
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cls.t3 = Tag.objects.create(name='t3', parent=cls.t1)
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cls.t4 = Tag.objects.create(name='t4', parent=cls.t3)
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cls.t5 = Tag.objects.create(name='t5', parent=cls.t3)
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cls.p1_o1 = Staff.objects.create(id=1, name="p1", organisation="o1")
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cls.p2_o1 = Staff.objects.create(id=2, name="p2", organisation="o1")
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cls.p3_o1 = Staff.objects.create(id=3, name="p3", organisation="o1")
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cls.p1_o2 = Staff.objects.create(id=4, name="p1", organisation="o2")
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cls.p1_o1.coworkers.add(cls.p2_o1, cls.p3_o1)
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cls.st1 = StaffTag.objects.create(staff=cls.p1_o1, tag=cls.t1)
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StaffTag.objects.create(staff=cls.p1_o1, tag=cls.t1)
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cls.celeb1 = Celebrity.objects.create(name="c1")
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cls.celeb2 = Celebrity.objects.create(name="c2")
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cls.fan1 = Fan.objects.create(fan_of=cls.celeb1)
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cls.fan2 = Fan.objects.create(fan_of=cls.celeb1)
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cls.fan3 = Fan.objects.create(fan_of=cls.celeb2)
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def test_basic_distinct_on(self):
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"""QuerySet.distinct('field', ...) works"""
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# (qset, expected) tuples
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qsets = (
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(
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Staff.objects.distinct().order_by('name'),
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[self.p1_o1, self.p1_o2, self.p2_o1, self.p3_o1],
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),
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(
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Staff.objects.distinct('name').order_by('name'),
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[self.p1_o1, self.p2_o1, self.p3_o1],
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),
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(
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Staff.objects.distinct('organisation').order_by('organisation', 'name'),
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[self.p1_o1, self.p1_o2],
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),
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(
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Staff.objects.distinct('name', 'organisation').order_by('name', 'organisation'),
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[self.p1_o1, self.p1_o2, self.p2_o1, self.p3_o1],
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),
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(
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Celebrity.objects.filter(fan__in=[self.fan1, self.fan2, self.fan3]).distinct('name').order_by('name'),
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[self.celeb1, self.celeb2],
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),
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# Does combining querysets work?
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(
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(Celebrity.objects.filter(fan__in=[self.fan1, self.fan2]).
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distinct('name').order_by('name') |
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Celebrity.objects.filter(fan__in=[self.fan3]).
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distinct('name').order_by('name')),
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[self.celeb1, self.celeb2],
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),
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(StaffTag.objects.distinct('staff', 'tag'), [self.st1]),
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(
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Tag.objects.order_by('parent__pk', 'pk').distinct('parent'),
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[self.t2, self.t4, self.t1]
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if connection.features.nulls_order_largest
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else [self.t1, self.t2, self.t4],
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),
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(
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StaffTag.objects.select_related('staff').distinct('staff__name').order_by('staff__name'),
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[self.st1],
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),
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# Fetch the alphabetically first coworker for each worker
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(
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(Staff.objects.distinct('id').order_by('id', 'coworkers__name').
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values_list('id', 'coworkers__name')),
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[(1, 'p2'), (2, 'p1'), (3, 'p1'), (4, None)],
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),
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)
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for qset, expected in qsets:
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self.assertSequenceEqual(qset, expected)
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self.assertEqual(qset.count(), len(expected))
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# Combining queries with different distinct_fields is not allowed.
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base_qs = Celebrity.objects.all()
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with self.assertRaisesMessage(AssertionError, "Cannot combine queries with different distinct fields."):
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base_qs.distinct('id') & base_qs.distinct('name')
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# Test join unreffing
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c1 = Celebrity.objects.distinct('greatest_fan__id', 'greatest_fan__fan_of')
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self.assertIn('OUTER JOIN', str(c1.query))
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c2 = c1.distinct('pk')
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self.assertNotIn('OUTER JOIN', str(c2.query))
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def test_sliced_queryset(self):
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msg = 'Cannot create distinct fields once a slice has been taken.'
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with self.assertRaisesMessage(TypeError, msg):
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Staff.objects.all()[0:5].distinct('name')
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def test_transform(self):
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new_name = self.t1.name.upper()
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self.assertNotEqual(self.t1.name, new_name)
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Tag.objects.create(name=new_name)
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with register_lookup(CharField, Lower):
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self.assertCountEqual(
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Tag.objects.order_by().distinct('name__lower'),
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[self.t1, self.t2, self.t3, self.t4, self.t5],
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)
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def test_distinct_not_implemented_checks(self):
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# distinct + annotate not allowed
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msg = 'annotate() + distinct(fields) is not implemented.'
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with self.assertRaisesMessage(NotImplementedError, msg):
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Celebrity.objects.annotate(Max('id')).distinct('id')[0]
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with self.assertRaisesMessage(NotImplementedError, msg):
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Celebrity.objects.distinct('id').annotate(Max('id'))[0]
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# However this check is done only when the query executes, so you
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# can use distinct() to remove the fields before execution.
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Celebrity.objects.distinct('id').annotate(Max('id')).distinct()[0]
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# distinct + aggregate not allowed
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msg = 'aggregate() + distinct(fields) not implemented.'
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with self.assertRaisesMessage(NotImplementedError, msg):
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Celebrity.objects.distinct('id').aggregate(Max('id'))
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def test_distinct_on_in_ordered_subquery(self):
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qs = Staff.objects.distinct('name').order_by('name', 'id')
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qs = Staff.objects.filter(pk__in=qs).order_by('name')
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self.assertSequenceEqual(qs, [self.p1_o1, self.p2_o1, self.p3_o1])
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qs = Staff.objects.distinct('name').order_by('name', '-id')
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qs = Staff.objects.filter(pk__in=qs).order_by('name')
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self.assertSequenceEqual(qs, [self.p1_o2, self.p2_o1, self.p3_o1])
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def test_distinct_on_get_ordering_preserved(self):
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"""
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Ordering shouldn't be cleared when distinct on fields are specified.
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refs #25081
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"""
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staff = Staff.objects.distinct('name').order_by('name', '-organisation').get(name='p1')
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self.assertEqual(staff.organisation, 'o2')
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