text: from math import ceil
  from operator import attrgetter
  
  from django.db import IntegrityError, NotSupportedError, connection
  from django.db.models import FileField, Value
  from django.db.models.functions import Lower
  from django.test import (
      TestCase, override_settings, skipIfDBFeature, skipUnlessDBFeature,
  )
  
  from .models import (
      BigAutoFieldModel, Country, NoFields, NullableFields, Pizzeria,
      ProxyCountry, ProxyMultiCountry, ProxyMultiProxyCountry, ProxyProxyCountry,
      Restaurant, SmallAutoFieldModel, State, TwoFields,
  )
  
  
  class BulkCreateTests(TestCase):
      def setUp(self):
          self.data = [
              Country(name="United States of America", iso_two_letter="US"),
              Country(name="The Netherlands", iso_two_letter="NL"),
              Country(name="Germany", iso_two_letter="DE"),
              Country(name="Czech Republic", iso_two_letter="CZ")
          ]
  
      def test_simple(self):
          created = Country.objects.bulk_create(self.data)
          self.assertEqual(created, self.data)
          self.assertQuerysetEqual(Country.objects.order_by("-name"), [
              "United States of America", "The Netherlands", "Germany", "Czech Republic"
          ], attrgetter("name"))
  
          created = Country.objects.bulk_create([])
          self.assertEqual(created, [])
          self.assertEqual(Country.objects.count(), 4)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_efficiency(self):
          with self.assertNumQueries(1):
              Country.objects.bulk_create(self.data)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_long_non_ascii_text(self):
          """
          Inserting non-ASCII values with a length in the range 2001 to 4000
          characters, i.e. 4002 to 8000 bytes, must be set as a CLOB on Oracle
          (#22144).
          """
          Country.objects.bulk_create([Country(description='Ж' * 3000)])
          self.assertEqual(Country.objects.count(), 1)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_long_and_short_text(self):
          Country.objects.bulk_create([
              Country(description='a' * 4001),
              Country(description='a'),
              Country(description='Ж' * 2001),
              Country(description='Ж'),
          ])
          self.assertEqual(Country.objects.count(), 4)
  
      def test_multi_table_inheritance_unsupported(self):
          expected_message = "Can't bulk create a multi-table inherited model"
          with self.assertRaisesMessage(ValueError, expected_message):
              Pizzeria.objects.bulk_create([
                  Pizzeria(name="The Art of Pizza"),
              ])
          with self.assertRaisesMessage(ValueError, expected_message):
              ProxyMultiCountry.objects.bulk_create([
                  ProxyMultiCountry(name="Fillory", iso_two_letter="FL"),
              ])
          with self.assertRaisesMessage(ValueError, expected_message):
              ProxyMultiProxyCountry.objects.bulk_create([
                  ProxyMultiProxyCountry(name="Fillory", iso_two_letter="FL"),
              ])
  
      def test_proxy_inheritance_supported(self):
          ProxyCountry.objects.bulk_create([
              ProxyCountry(name="Qwghlm", iso_two_letter="QW"),
              Country(name="Tortall", iso_two_letter="TA"),
          ])
          self.assertQuerysetEqual(ProxyCountry.objects.all(), {
              "Qwghlm", "Tortall"
          }, attrgetter("name"), ordered=False)
  
          ProxyProxyCountry.objects.bulk_create([
              ProxyProxyCountry(name="Netherlands", iso_two_letter="NT"),
          ])
          self.assertQuerysetEqual(ProxyProxyCountry.objects.all(), {
              "Qwghlm", "Tortall", "Netherlands",
          }, attrgetter("name"), ordered=False)
  
      def test_non_auto_increment_pk(self):
          State.objects.bulk_create([
              State(two_letter_code=s)
              for s in ["IL", "NY", "CA", "ME"]
          ])
          self.assertQuerysetEqual(State.objects.order_by("two_letter_code"), [
              "CA", "IL", "ME", "NY",
          ], attrgetter("two_letter_code"))
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_non_auto_increment_pk_efficiency(self):
          with self.assertNumQueries(1):
              State.objects.bulk_create([
                  State(two_letter_code=s)
                  for s in ["IL", "NY", "CA", "ME"]
              ])
          self.assertQuerysetEqual(State.objects.order_by("two_letter_code"), [
              "CA", "IL", "ME", "NY",
          ], attrgetter("two_letter_code"))
  
      @skipIfDBFeature('allows_auto_pk_0')
      def test_zero_as_autoval(self):
          """
          Zero as id for AutoField should raise exception in MySQL, because MySQL
          does not allow zero for automatic primary key if the
          NO_AUTO_VALUE_ON_ZERO SQL mode is not enabled.
          """
          valid_country = Country(name='Germany', iso_two_letter='DE')
          invalid_country = Country(id=0, name='Poland', iso_two_letter='PL')
          msg = 'The database backend does not accept 0 as a value for AutoField.'
          with self.assertRaisesMessage(ValueError, msg):
              Country.objects.bulk_create([valid_country, invalid_country])
  
      def test_batch_same_vals(self):
          # SQLite had a problem where all the same-valued models were
          # collapsed to one insert.
          Restaurant.objects.bulk_create([
              Restaurant(name='foo') for i in range(0, 2)
          ])
          self.assertEqual(Restaurant.objects.count(), 2)
  
      def test_large_batch(self):
          TwoFields.objects.bulk_create([
              TwoFields(f1=i, f2=i + 1) for i in range(0, 1001)
          ])
          self.assertEqual(TwoFields.objects.count(), 1001)
          self.assertEqual(
              TwoFields.objects.filter(f1__gte=450, f1__lte=550).count(),
              101)
          self.assertEqual(TwoFields.objects.filter(f2__gte=901).count(), 101)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_large_single_field_batch(self):
          # SQLite had a problem with more than 500 UNIONed selects in single
          # query.
          Restaurant.objects.bulk_create([
              Restaurant() for i in range(0, 501)
          ])
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_large_batch_efficiency(self):
          with override_settings(DEBUG=True):
              connection.queries_log.clear()
              TwoFields.objects.bulk_create([
                  TwoFields(f1=i, f2=i + 1) for i in range(0, 1001)
              ])
              self.assertLess(len(connection.queries), 10)
  
      def test_large_batch_mixed(self):
          """
          Test inserting a large batch with objects having primary key set
          mixed together with objects without PK set.
          """
          TwoFields.objects.bulk_create([
              TwoFields(id=i if i % 2 == 0 else None, f1=i, f2=i + 1)
              for i in range(100000, 101000)
          ])
          self.assertEqual(TwoFields.objects.count(), 1000)
          # We can't assume much about the ID's created, except that the above
          # created IDs must exist.
          id_range = range(100000, 101000, 2)
          self.assertEqual(TwoFields.objects.filter(id__in=id_range).count(), 500)
          self.assertEqual(TwoFields.objects.exclude(id__in=id_range).count(), 500)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_large_batch_mixed_efficiency(self):
          """
          Test inserting a large batch with objects having primary key set
          mixed together with objects without PK set.
          """
          with override_settings(DEBUG=True):
              connection.queries_log.clear()
              TwoFields.objects.bulk_create([
                  TwoFields(id=i if i % 2 == 0 else None, f1=i, f2=i + 1)
                  for i in range(100000, 101000)])
              self.assertLess(len(connection.queries), 10)
  
      def test_explicit_batch_size(self):
          objs = [TwoFields(f1=i, f2=i) for i in range(0, 4)]
          num_objs = len(objs)
          TwoFields.objects.bulk_create(objs, batch_size=1)
          self.assertEqual(TwoFields.objects.count(), num_objs)
          TwoFields.objects.all().delete()
          TwoFields.objects.bulk_create(objs, batch_size=2)
          self.assertEqual(TwoFields.objects.count(), num_objs)
          TwoFields.objects.all().delete()
          TwoFields.objects.bulk_create(objs, batch_size=3)
          self.assertEqual(TwoFields.objects.count(), num_objs)
          TwoFields.objects.all().delete()
          TwoFields.objects.bulk_create(objs, batch_size=num_objs)
          self.assertEqual(TwoFields.objects.count(), num_objs)
  
      def test_empty_model(self):
          NoFields.objects.bulk_create([NoFields() for i in range(2)])
          self.assertEqual(NoFields.objects.count(), 2)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_explicit_batch_size_efficiency(self):
          objs = [TwoFields(f1=i, f2=i) for i in range(0, 100)]
          with self.assertNumQueries(2):
              TwoFields.objects.bulk_create(objs, 50)
          TwoFields.objects.all().delete()
          with self.assertNumQueries(1):
              TwoFields.objects.bulk_create(objs, len(objs))
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_explicit_batch_size_respects_max_batch_size(self):
          objs = [Country() for i in range(1000)]
          fields = ['name', 'iso_two_letter', 'description']
          max_batch_size = max(connection.ops.bulk_batch_size(fields, objs), 1)
          with self.assertNumQueries(ceil(len(objs) / max_batch_size)):
              Country.objects.bulk_create(objs, batch_size=max_batch_size + 1)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_bulk_insert_expressions(self):
          Restaurant.objects.bulk_create([
              Restaurant(name="Sam's Shake Shack"),
              Restaurant(name=Lower(Value("Betty's Beetroot Bar")))
          ])
          bbb = Restaurant.objects.filter(name="betty's beetroot bar")
          self.assertEqual(bbb.count(), 1)
  
      @skipUnlessDBFeature('has_bulk_insert')
      def test_bulk_insert_nullable_fields(self):
          fk_to_auto_fields = {
              'auto_field': NoFields.objects.create(),
              'small_auto_field': SmallAutoFieldModel.objects.create(),
              'big_auto_field': BigAutoFieldModel.objects.create(),
          }
          # NULL can be mixed with other values in nullable fields
          nullable_fields = [field for field in NullableFields._meta.get_fields() if field.name != 'id']
          NullableFields.objects.bulk_create([
              NullableFields(**{**fk_to_auto_fields, field.name: None})
              for field in nullable_fields
          ])
          self.assertEqual(NullableFields.objects.count(), len(nullable_fields))
          for field in nullable_fields:
              with self.subTest(field=field):
                  field_value = '' if isinstance(field, FileField) else None
                  self.assertEqual(NullableFields.objects.filter(**{field.name: field_value}).count(), 1)
  
      @skipUnlessDBFeature('can_return_rows_from_bulk_insert')
      def test_set_pk_and_insert_single_item(self):
          with self.assertNumQueries(1):
              countries = Country.objects.bulk_create([self.data[0]])
          self.assertEqual(len(countries), 1)
          self.assertEqual(Country.objects.get(pk=countries[0].pk), countries[0])
  
      @skipUnlessDBFeature('can_return_rows_from_bulk_insert')
      def test_set_pk_and_query_efficiency(self):
          with self.assertNumQueries(1):
              countries = Country.objects.bulk_create(self.data)
          self.assertEqual(len(countries), 4)
          self.assertEqual(Country.objects.get(pk=countries[0].pk), countries[0])
          self.assertEqual(Country.objects.get(pk=countries[1].pk), countries[1])
          self.assertEqual(Country.objects.get(pk=countries[2].pk), countries[2])
          self.assertEqual(Country.objects.get(pk=countries[3].pk), countries[3])
  
      @skipUnlessDBFeature('can_return_rows_from_bulk_insert')
      def test_set_state(self):
          country_nl = Country(name='Netherlands', iso_two_letter='NL')
          country_be = Country(name='Belgium', iso_two_letter='BE')
          Country.objects.bulk_create([country_nl])
          country_be.save()
          # Objects save via bulk_create() and save() should have equal state.
          self.assertEqual(country_nl._state.adding, country_be._state.adding)
          self.assertEqual(country_nl._state.db, country_be._state.db)
  
      def test_set_state_with_pk_specified(self):
          state_ca = State(two_letter_code='CA')
          state_ny = State(two_letter_code='NY')
          State.objects.bulk_create([state_ca])
          state_ny.save()
          # Objects save via bulk_create() and save() should have equal state.
          self.assertEqual(state_ca._state.adding, state_ny._state.adding)
          self.assertEqual(state_ca._state.db, state_ny._state.db)
  
      @skipIfDBFeature('supports_ignore_conflicts')
      def test_ignore_conflicts_value_error(self):
          message = 'This database backend does not support ignoring conflicts.'
          with self.assertRaisesMessage(NotSupportedError, message):
              TwoFields.objects.bulk_create(self.data, ignore_conflicts=True)
  
      @skipUnlessDBFeature('supports_ignore_conflicts')
      def test_ignore_conflicts_ignore(self):
          data = [
              TwoFields(f1=1, f2=1),
              TwoFields(f1=2, f2=2),
              TwoFields(f1=3, f2=3),
          ]
          TwoFields.objects.bulk_create(data)
          self.assertEqual(TwoFields.objects.count(), 3)
          # With ignore_conflicts=True, conflicts are ignored.
          conflicting_objects = [
              TwoFields(f1=2, f2=2),
              TwoFields(f1=3, f2=3),
          ]
          TwoFields.objects.bulk_create([conflicting_objects[0]], ignore_conflicts=True)
          TwoFields.objects.bulk_create(conflicting_objects, ignore_conflicts=True)
          self.assertEqual(TwoFields.objects.count(), 3)
          self.assertIsNone(conflicting_objects[0].pk)
          self.assertIsNone(conflicting_objects[1].pk)
          # New objects are created and conflicts are ignored.
          new_object = TwoFields(f1=4, f2=4)
          TwoFields.objects.bulk_create(conflicting_objects + [new_object], ignore_conflicts=True)
          self.assertEqual(TwoFields.objects.count(), 4)
          self.assertIsNone(new_object.pk)
          # Without ignore_conflicts=True, there's a problem.
          with self.assertRaises(IntegrityError):
              TwoFields.objects.bulk_create(conflicting_objects)
  
      def test_nullable_fk_after_parent(self):
          parent = NoFields()
          child = NullableFields(auto_field=parent, integer_field=88)
          parent.save()
          NullableFields.objects.bulk_create([child])
          child = NullableFields.objects.get(integer_field=88)
          self.assertEqual(child.auto_field, parent)
  
      @skipUnlessDBFeature('can_return_rows_from_bulk_insert')
      def test_nullable_fk_after_parent_bulk_create(self):
          parent = NoFields()
          child = NullableFields(auto_field=parent, integer_field=88)
          NoFields.objects.bulk_create([parent])
          NullableFields.objects.bulk_create([child])
          child = NullableFields.objects.get(integer_field=88)
          self.assertEqual(child.auto_field, parent)
  
      def test_unsaved_parent(self):
          parent = NoFields()
          msg = (
              "bulk_create() prohibited to prevent data loss due to unsaved "
              "related object 'auto_field'."
          )
          with self.assertRaisesMessage(ValueError, msg):
              NullableFields.objects.bulk_create([NullableFields(auto_field=parent)])
  
      def test_invalid_batch_size_exception(self):
          msg = 'Batch size must be a positive integer.'
          with self.assertRaisesMessage(ValueError, msg):
              Country.objects.bulk_create([], batch_size=-1)
  