mirror of https://github.com/django/django.git
Added a ManyToManyField(db_constraint=False) option, this allows not creating constraints on the intermediary models.
This commit is contained in:
Alex Gaynor
parent
4cccb85e29
commit
bbbd698c7a
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@ -955,7 +955,9 @@ class OneToOneRel(ManyToOneRel):
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class ManyToManyRel(object):
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def __init__(self, to, related_name=None, limit_choices_to=None,
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symmetrical=True, through=None):
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symmetrical=True, through=None, db_constraint=True):
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if through and not db_constraint:
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raise ValueError("Can't supply a through model and db_constraint=False")
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self.to = to
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self.related_name = related_name
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if limit_choices_to is None:
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@ -964,6 +966,7 @@ class ManyToManyRel(object):
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self.symmetrical = symmetrical
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self.multiple = True
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self.through = through
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self.db_constraint = db_constraint
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def is_hidden(self):
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"Should the related object be hidden?"
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@ -1196,15 +1199,15 @@ def create_many_to_many_intermediary_model(field, klass):
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return type(name, (models.Model,), {
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'Meta': meta,
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'__module__': klass.__module__,
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from_: models.ForeignKey(klass, related_name='%s+' % name, db_tablespace=field.db_tablespace),
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to: models.ForeignKey(to_model, related_name='%s+' % name, db_tablespace=field.db_tablespace)
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from_: models.ForeignKey(klass, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.rel.db_constraint),
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to: models.ForeignKey(to_model, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.rel.db_constraint)
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})
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class ManyToManyField(RelatedField, Field):
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description = _("Many-to-many relationship")
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def __init__(self, to, **kwargs):
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def __init__(self, to, db_constraint=True, **kwargs):
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try:
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assert not to._meta.abstract, "%s cannot define a relation with abstract class %s" % (self.__class__.__name__, to._meta.object_name)
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except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
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@ -1219,13 +1222,15 @@ class ManyToManyField(RelatedField, Field):
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related_name=kwargs.pop('related_name', None),
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limit_choices_to=kwargs.pop('limit_choices_to', None),
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symmetrical=kwargs.pop('symmetrical', to == RECURSIVE_RELATIONSHIP_CONSTANT),
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through=kwargs.pop('through', None))
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through=kwargs.pop('through', None),
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db_constraint=db_constraint,
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)
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self.db_table = kwargs.pop('db_table', None)
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if kwargs['rel'].through is not None:
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assert self.db_table is None, "Cannot specify a db_table if an intermediary model is used."
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Field.__init__(self, **kwargs)
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super(ManyToManyField, self).__init__(**kwargs)
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msg = _('Hold down "Control", or "Command" on a Mac, to select more than one.')
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self.help_text = string_concat(self.help_text, ' ', msg)
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@ -1227,6 +1227,20 @@ that control how the relationship functions.
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the table for the model defining the relationship and the name of the field
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itself.
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.. attribute:: ManyToManyField.db_constraint
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Controls whether or not constraints should be created in the database for
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the foreign keys in the intermediary table. The default is ``True``, and
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that's almost certainly what you want; setting this to ``False`` can be
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very bad for data integrity. That said, here are some scenarios where you
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might want to do this:
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* You have legacy data that is not valid.
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* You're sharding your database.
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It is an error to pass both ``db_constraint`` and ``through``.
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.. _ref-onetoone:
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``OneToOneField``
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@ -113,8 +113,8 @@ Minor features
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* The ``MemcachedCache`` cache backend now uses the latest :mod:`pickle`
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protocol available.
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* Added the :attr:`django.db.models.ForeignKey.db_constraint`
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option.
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* Added the :attr:`django.db.models.ForeignKey.db_constraint` and
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:attr:`django.db.models.ManyToManyField.db_constraint` options.
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* The jQuery library embedded in the admin has been upgraded to version 1.9.1.
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@ -90,7 +90,10 @@ class Item(models.Model):
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@python_2_unicode_compatible
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class Object(models.Model):
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pass
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related_objects = models.ManyToManyField("self", db_constraint=False, symmetrical=False)
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def __str__(self):
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return str(self.id)
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@python_2_unicode_compatible
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@ -12,13 +12,12 @@ from django.db import (backend, connection, connections, DEFAULT_DB_ALIAS,
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from django.db.backends.signals import connection_created
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from django.db.backends.postgresql_psycopg2 import version as pg_version
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from django.db.models import Sum, Avg, Variance, StdDev
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from django.db.utils import ConnectionHandler, DatabaseError
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from django.db.utils import ConnectionHandler
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from django.test import (TestCase, skipUnlessDBFeature, skipIfDBFeature,
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TransactionTestCase)
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from django.test.utils import override_settings, str_prefix
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from django.utils import six
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from django.utils import six, unittest
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from django.utils.six.moves import xrange
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from django.utils import unittest
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from . import models
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@ -52,7 +51,7 @@ class OracleChecks(unittest.TestCase):
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convert_unicode = backend.convert_unicode
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cursor = connection.cursor()
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cursor.callproc(convert_unicode('DBMS_SESSION.SET_IDENTIFIER'),
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[convert_unicode('_django_testing!'),])
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[convert_unicode('_django_testing!')])
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@unittest.skipUnless(connection.vendor == 'oracle',
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"No need to check Oracle cursor semantics")
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@ -99,6 +98,7 @@ class OracleChecks(unittest.TestCase):
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c.execute(query)
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self.assertEqual(c.fetchone()[0], 1)
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class MySQLTests(TestCase):
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@unittest.skipUnless(connection.vendor == 'mysql',
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"Test valid only for MySQL")
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@ -182,6 +182,7 @@ class LastExecutedQueryTest(TestCase):
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self.assertEqual(connection.queries[-1]['sql'],
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str_prefix("QUERY = %(_)s\"SELECT strftime('%%Y', 'now');\" - PARAMS = ()"))
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class ParameterHandlingTest(TestCase):
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def test_bad_parameter_count(self):
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"An executemany call with too many/not enough parameters will raise an exception (Refs #12612)"
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@ -191,8 +192,9 @@ class ParameterHandlingTest(TestCase):
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connection.ops.quote_name('root'),
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connection.ops.quote_name('square')
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))
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self.assertRaises(Exception, cursor.executemany, query, [(1,2,3),])
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self.assertRaises(Exception, cursor.executemany, query, [(1,),])
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self.assertRaises(Exception, cursor.executemany, query, [(1, 2, 3)])
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self.assertRaises(Exception, cursor.executemany, query, [(1,)])
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# Unfortunately, the following tests would be a good test to run on all
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# backends, but it breaks MySQL hard. Until #13711 is fixed, it can't be run
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@ -240,6 +242,7 @@ class LongNameTest(TestCase):
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for statement in connection.ops.sql_flush(no_style(), tables, sequences):
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cursor.execute(statement)
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class SequenceResetTest(TestCase):
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def test_generic_relation(self):
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"Sequence names are correct when resetting generic relations (Ref #13941)"
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@ -257,6 +260,7 @@ class SequenceResetTest(TestCase):
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obj = models.Post.objects.create(name='New post', text='goodbye world')
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self.assertTrue(obj.pk > 10)
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class PostgresVersionTest(TestCase):
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def assert_parses(self, version_string, version):
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self.assertEqual(pg_version._parse_version(version_string), version)
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@ -291,6 +295,7 @@ class PostgresVersionTest(TestCase):
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conn = OlderConnectionMock()
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self.assertEqual(pg_version.get_version(conn), 80300)
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class PostgresNewConnectionTest(TestCase):
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"""
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#17062: PostgreSQL shouldn't roll back SET TIME ZONE, even if the first
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@ -338,17 +343,18 @@ class ConnectionCreatedSignalTest(TestCase):
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@skipUnlessDBFeature('test_db_allows_multiple_connections')
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def test_signal(self):
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data = {}
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def receiver(sender, connection, **kwargs):
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data["connection"] = connection
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connection_created.connect(receiver)
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connection.close()
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cursor = connection.cursor()
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connection.cursor()
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self.assertTrue(data["connection"].connection is connection.connection)
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connection_created.disconnect(receiver)
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data.clear()
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cursor = connection.cursor()
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connection.cursor()
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self.assertTrue(data == {})
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@ -443,7 +449,7 @@ class BackendTestCase(TestCase):
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old_password = connection.settings_dict['PASSWORD']
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connection.settings_dict['PASSWORD'] = "françois"
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try:
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cursor = connection.cursor()
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connection.cursor()
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except DatabaseError:
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# As password is probably wrong, a database exception is expected
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pass
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@ -470,6 +476,7 @@ class BackendTestCase(TestCase):
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with self.assertRaises(DatabaseError):
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cursor.execute(query)
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# We don't make these tests conditional because that means we would need to
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# check and differentiate between:
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# * MySQL+InnoDB, MySQL+MYISAM (something we currently can't do).
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@ -477,7 +484,6 @@ class BackendTestCase(TestCase):
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# on or not, something that would be controlled by runtime support and user
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# preference.
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# verify if its type is django.database.db.IntegrityError.
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class FkConstraintsTests(TransactionTestCase):
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def setUp(self):
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@ -581,6 +587,7 @@ class ThreadTests(TestCase):
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connections_dict = {}
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connection.cursor()
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connections_dict[id(connection)] = connection
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def runner():
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# Passing django.db.connection between threads doesn't work while
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# connections[DEFAULT_DB_ALIAS] does.
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@ -616,6 +623,7 @@ class ThreadTests(TestCase):
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connections_dict = {}
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for conn in connections.all():
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connections_dict[id(conn)] = conn
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def runner():
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from django.db import connections
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for conn in connections.all():
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@ -682,6 +690,7 @@ class ThreadTests(TestCase):
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"""
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# First, without explicitly enabling the connection for sharing.
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exceptions = set()
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def runner1():
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def runner2(other_thread_connection):
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try:
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@ -699,6 +708,7 @@ class ThreadTests(TestCase):
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# Then, with explicitly enabling the connection for sharing.
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exceptions = set()
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def runner1():
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def runner2(other_thread_connection):
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try:
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@ -746,3 +756,14 @@ class DBConstraintTestCase(TransactionTestCase):
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with self.assertRaises(models.Object.DoesNotExist):
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ref.obj
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def test_many_to_many(self):
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obj = models.Object.objects.create()
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obj.related_objects.create()
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self.assertEqual(models.Object.objects.count(), 2)
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self.assertEqual(obj.related_objects.count(), 1)
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intermediary_model = models.Object._meta.get_field_by_name("related_objects")[0].rel.through
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intermediary_model.objects.create(from_object_id=obj.id, to_object_id=12345)
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self.assertEqual(obj.related_objects.count(), 1)
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self.assertEqual(intermediary_model.objects.count(), 2)
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