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Fixed #32776 -- Added support for Array subqueries on PostgreSQL.
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@ -0,0 +1,14 @@
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from django.contrib.postgres.fields import ArrayField
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from django.db.models import Subquery
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from django.utils.functional import cached_property
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class ArraySubquery(Subquery):
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template = 'ARRAY(%(subquery)s)'
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def __init__(self, queryset, **kwargs):
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super().__init__(queryset, **kwargs)
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@cached_property
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def output_field(self):
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return ArrayField(self.query.output_field)
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@ -0,0 +1,37 @@
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=====================================
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PostgreSQL specific query expressions
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=====================================
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.. module:: django.contrib.postgres.expressions
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:synopsis: PostgreSQL specific query expressions
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These expressions are available from the
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``django.contrib.postgres.expressions`` module.
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``ArraySubquery()`` expressions
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===============================
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.. class:: ArraySubquery(queryset)
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.. versionadded:: 4.0
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``ArraySubquery`` is a :class:`~django.db.models.Subquery` that uses the
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PostgreSQL ``ARRAY`` constructor to build a list of values from the queryset,
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which must use :meth:`.QuerySet.values` to return only a single column.
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This class differs from :class:`~django.contrib.postgres.aggregates.ArrayAgg`
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in the way that it does not act as an aggregate function and does not require
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an SQL ``GROUP BY`` clause to build the list of values.
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For example, if you want to annotate all related books to an author as JSON
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objects::
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>>> from django.db.models import OuterRef
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>>> from django.db.models.functions import JSONObject
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>>> from django.contrib.postgres.expressions import ArraySubquery
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>>> books = Book.objects.filter(author=OuterRef('pk')).values(
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... json=JSONObject(title='title', pages='pages')
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... )
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>>> author = Author.objects.annotate(books=ArraySubquery(books)).first()
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>>> author.books
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[{'title': 'Solaris', 'pages': 204}, {'title': 'The Cyberiad', 'pages': 295}]
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@ -30,6 +30,7 @@ a number of PostgreSQL specific data types.
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aggregates
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constraints
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expressions
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fields
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forms
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functions
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@ -131,6 +131,11 @@ Minor features
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:class:`~django.contrib.postgres.operations.AddConstraintNotValid` on
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PostgreSQL.
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* The new
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:class:`ArraySubquery() <django.contrib.postgres.expressions.ArraySubquery>`
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expression allows using subqueries to construct lists of values on
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PostgreSQL.
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:mod:`django.contrib.redirects`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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@ -10,7 +10,7 @@ from django.core.exceptions import FieldError
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from django.core.management import call_command
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from django.db import IntegrityError, connection, models
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from django.db.models.expressions import Exists, OuterRef, RawSQL, Value
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from django.db.models.functions import Cast, Upper
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from django.db.models.functions import Cast, JSONObject, Upper
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from django.test import TransactionTestCase, modify_settings, override_settings
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from django.test.utils import isolate_apps
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from django.utils import timezone
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@ -28,6 +28,7 @@ try:
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from psycopg2.extras import NumericRange
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from django.contrib.postgres.aggregates import ArrayAgg
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from django.contrib.postgres.expressions import ArraySubquery
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from django.contrib.postgres.fields import ArrayField
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from django.contrib.postgres.fields.array import (
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IndexTransform, SliceTransform,
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@ -551,6 +552,66 @@ class TestQuerying(PostgreSQLTestCase):
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1,
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)
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def test_filter_by_array_subquery(self):
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inner_qs = NullableIntegerArrayModel.objects.filter(
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field__len=models.OuterRef('field__len'),
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).values('field')
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self.assertSequenceEqual(
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NullableIntegerArrayModel.objects.alias(
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same_sized_fields=ArraySubquery(inner_qs),
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).filter(same_sized_fields__len__gt=1),
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self.objs[0:2],
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)
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def test_annotated_array_subquery(self):
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inner_qs = NullableIntegerArrayModel.objects.exclude(
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pk=models.OuterRef('pk')
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).values('order')
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self.assertSequenceEqual(
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NullableIntegerArrayModel.objects.annotate(
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sibling_ids=ArraySubquery(inner_qs),
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).get(order=1).sibling_ids,
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[2, 3, 4, 5],
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)
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def test_group_by_with_annotated_array_subquery(self):
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inner_qs = NullableIntegerArrayModel.objects.exclude(
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pk=models.OuterRef('pk')
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).values('order')
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self.assertSequenceEqual(
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NullableIntegerArrayModel.objects.annotate(
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sibling_ids=ArraySubquery(inner_qs),
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sibling_count=models.Max('sibling_ids__len'),
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).values_list('sibling_count', flat=True),
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[len(self.objs) - 1] * len(self.objs),
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)
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def test_annotated_ordered_array_subquery(self):
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inner_qs = NullableIntegerArrayModel.objects.order_by('-order').values('order')
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self.assertSequenceEqual(
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NullableIntegerArrayModel.objects.annotate(
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ids=ArraySubquery(inner_qs),
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).first().ids,
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[5, 4, 3, 2, 1],
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)
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def test_annotated_array_subquery_with_json_objects(self):
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inner_qs = NullableIntegerArrayModel.objects.exclude(
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pk=models.OuterRef('pk')
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).values(json=JSONObject(order='order', field='field'))
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siblings_json = NullableIntegerArrayModel.objects.annotate(
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siblings_json=ArraySubquery(inner_qs),
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).values_list('siblings_json', flat=True).get(order=1)
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self.assertSequenceEqual(
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siblings_json,
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[
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{'field': [2], 'order': 2},
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{'field': [2, 3], 'order': 3},
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{'field': [20, 30, 40], 'order': 4},
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{'field': None, 'order': 5},
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],
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)
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class TestDateTimeExactQuerying(PostgreSQLTestCase):
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