diff --git a/django/core/management/commands/loaddata.py b/django/core/management/commands/loaddata.py
index 34f3543..0aa07f4 100644
--- a/django/core/management/commands/loaddata.py
+++ b/django/core/management/commands/loaddata.py
@@ -1,3 +1,7 @@
+# This is necessary in Python 2.5 to enable the with statement, in 2.6
+# and up it is no longer necessary.
+from __future__ import with_statement
+
 import sys
 import os
 import gzip
@@ -166,12 +170,20 @@ class Command(BaseCommand):
                                     (format, fixture_name, humanize(fixture_dir)))
                             try:
                                 objects = serializers.deserialize(format, fixture, using=using)
-                                for obj in objects:
-                                    objects_in_fixture += 1
-                                    if router.allow_syncdb(using, obj.object.__class__):
-                                        loaded_objects_in_fixture += 1
-                                        models.add(obj.object.__class__)
-                                        obj.save(using=using)
+                                
+                                with connection.constraint_checks_disabled():
+                                    for obj in objects:
+                                        objects_in_fixture += 1
+                                        if router.allow_syncdb(using, obj.object.__class__):
+                                            loaded_objects_in_fixture += 1
+                                            models.add(obj.object.__class__)
+                                            obj.save(using=using)
+                                        
+                                # Since we disabled constraint checks, we must manually check for
+                                # any invalid keys that might have been added
+                                table_names = [model._meta.db_table for model in models]
+                                connection.check_constraints(table_names=table_names)
+                                    
                                 loaded_object_count += loaded_objects_in_fixture
                                 fixture_object_count += objects_in_fixture
                                 label_found = True
diff --git a/django/db/__init__.py b/django/db/__init__.py
index 8395468..c6f28da 100644
--- a/django/db/__init__.py
+++ b/django/db/__init__.py
@@ -12,6 +12,7 @@ if DEFAULT_DB_ALIAS not in settings.DATABASES:
     raise ImproperlyConfigured("You must define a '%s' database" % DEFAULT_DB_ALIAS)
 
 connections = ConnectionHandler(settings.DATABASES)
+connections._ignore_num_queries = False
 
 router = ConnectionRouter(settings.DATABASE_ROUTERS)
 
diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 1c3bc7e..d0e997f 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -3,6 +3,7 @@ try:
 except ImportError:
     import dummy_thread as thread
 from threading import local
+from contextlib import contextmanager
 
 from django.conf import settings
 from django.db import DEFAULT_DB_ALIAS
@@ -33,6 +34,8 @@ class BaseDatabaseWrapper(local):
         self.transaction_state = []
         self.savepoint_state = 0
         self._dirty = None
+        
+        self.constraint_checking_disabled = False
 
     def __eq__(self, other):
         return self.alias == other.alias
@@ -237,6 +240,36 @@ class BaseDatabaseWrapper(local):
         """
         if self.savepoint_state:
             self._savepoint_commit(sid)
+    
+    @contextmanager
+    def constraint_checks_disabled(self):
+        self.disable_constraint_checking()
+        try:
+            yield
+        finally:
+            if self.constraint_checking_disabled:
+                self.enable_constraint_checking()
+        
+    
+    def disable_constraint_checking(self):
+        """
+        Backends can implement as needed to temporarily disable foreign key constraint
+        checking.
+        """
+        self.constraint_checking_disabled = True
+
+    def enable_constraint_checking(self):
+        """
+        Backends can implement as needed to re-enable foreign key constraint checking.
+        """
+        self.constraint_checking_disabled = False
+    
+    def check_constraints(self, table_names=None):
+        """
+        Backends can override this method if they can apply constraint checking (e.g. via "SET CONSTRAINTS
+        ALL IMMEDIATE"). Should raise an IntegrityError if any invalid foreign key references are encountered.
+        """
+        pass
 
     def close(self):
         if self.connection is not None:
@@ -869,6 +902,19 @@ class BaseDatabaseIntrospection(object):
 
         return sequence_list
 
+    def get_key_columns(self, cursor, table_name):
+        """
+        Backends can override this to return a list of (column_name, referenced_table_name,
+        referenced_column_name) for all key columns in given table.
+        """
+        raise NotImplementedError
+    
+    def get_primary_key_column(self, cursor, table_name):
+        """
+        Backends can override this to return the column name of the primary key for the given table.
+        """
+        raise NotImplementedError
+
 class BaseDatabaseClient(object):
     """
     This class encapsulates all backend-specific methods for opening a
diff --git a/django/db/backends/dummy/base.py b/django/db/backends/dummy/base.py
index 7de48c8..746f26b 100644
--- a/django/db/backends/dummy/base.py
+++ b/django/db/backends/dummy/base.py
@@ -34,6 +34,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
     get_table_description = complain
     get_relations = complain
     get_indexes = complain
+    get_key_columns = complain
 
 class DatabaseWrapper(BaseDatabaseWrapper):
     operators = {}
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index 6d02aa7..0d719b7 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -349,3 +349,53 @@ class DatabaseWrapper(BaseDatabaseWrapper):
                 raise Exception('Unable to determine MySQL version from version string %r' % self.connection.get_server_info())
             self.server_version = tuple([int(x) for x in m.groups()])
         return self.server_version
+
+    def disable_constraint_checking(self):
+        """
+        Disables foreign key checks, primarily for use in adding rows with forward references. Always returns True,
+        to indicate constraint checks need to be re-enabled.
+        """
+        self.cursor().execute('SET foreign_key_checks=0')
+        self.constraint_checking_disabled = True
+
+    def enable_constraint_checking(self):
+        """
+        Re-enable foreign key checks after they have been disabled.
+        """
+        self.cursor().execute('SET foreign_key_checks=1')
+        self.constraint_checking_disabled = False
+    
+    def check_constraints(self, table_names=None):
+        """
+        Checks each table name in table-names for rows with invalid foreign key references. This method is
+        intended to be used in conjunction with `disable_constraint_checking()` and `enable_constraint_checking()`, to
+        determine if rows with invalid references were entered while constraint checks were off.
+
+        Raises an IntegrityError on the first invalid foreign key reference encountered (if any) and provides
+        detailed information about the invalid reference in the error message.
+
+        Backends can override this method if they can more directly apply constraint checking (e.g. via "SET CONSTRAINTS
+        ALL IMMEDIATE")
+        """
+        cursor = self.cursor()
+        if table_names is None:
+            table_names = self.introspection.get_table_list(cursor)
+        for table_name in table_names:
+            primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
+            if not primary_key_column_name:
+                continue
+            key_columns = self.introspection.get_key_columns(cursor, table_name)
+            for column_name, referenced_table_name, referenced_column_name in key_columns:
+                cursor.execute("""
+                    SELECT REFERRING.`%s`, REFERRING.`%s` FROM `%s` as REFERRING
+                    LEFT JOIN `%s` as REFERRED
+                    ON (REFERRING.`%s` = REFERRED.`%s`)
+                    WHERE REFERRING.`%s` IS NOT NULL
+                        AND REFERRED.`%s` IS NULL"""
+                    % (primary_key_column_name, column_name, table_name, referenced_table_name,
+                       column_name, referenced_column_name, column_name, referenced_column_name))
+                for bad_row in cursor.fetchall():
+                    raise utils.IntegrityError("The row in table '%s' with primary key '%s' has an invalid \
+foreign key: %s.%s contains a value '%s' that does not have a corresponding value in %s.%s."
+                                         % (table_name, bad_row[0], table_name, column_name, bad_row[1],
+                                            referenced_table_name, referenced_column_name))
diff --git a/django/db/backends/mysql/introspection.py b/django/db/backends/mysql/introspection.py
index 9e1518b..4612221 100644
--- a/django/db/backends/mysql/introspection.py
+++ b/django/db/backends/mysql/introspection.py
@@ -51,10 +51,21 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
         representing all relationships to the given table. Indexes are 0-based.
         """
         my_field_dict = self._name_to_index(cursor, table_name)
-        constraints = []
+        constraints = self.get_key_columns(cursor, table_name)
         relations = {}
+        for my_fieldname, other_table, other_field in constraints:
+            other_field_index = self._name_to_index(cursor, other_table)[other_field]
+            my_field_index = my_field_dict[my_fieldname]
+            relations[my_field_index] = (other_field_index, other_table)
+        return relations
+
+    def get_key_columns(self, cursor, table_name):
+        """
+        Returns a list of (column_name, referenced_table_name, referenced_column_name) for all
+        key columns in given table.
+        """
+        key_columns = []
         try:
-            # This should work for MySQL 5.0.
             cursor.execute("""
                 SELECT column_name, referenced_table_name, referenced_column_name
                 FROM information_schema.key_column_usage
@@ -62,7 +73,7 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                     AND table_schema = DATABASE()
                     AND referenced_table_name IS NOT NULL
                     AND referenced_column_name IS NOT NULL""", [table_name])
-            constraints.extend(cursor.fetchall())
+            key_columns.extend(cursor.fetchall())
         except (ProgrammingError, OperationalError):
             # Fall back to "SHOW CREATE TABLE", for previous MySQL versions.
             # Go through all constraints and save the equal matches.
@@ -74,14 +85,17 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
                     if match == None:
                         break
                     pos = match.end()
-                    constraints.append(match.groups())
-
-        for my_fieldname, other_table, other_field in constraints:
-            other_field_index = self._name_to_index(cursor, other_table)[other_field]
-            my_field_index = my_field_dict[my_fieldname]
-            relations[my_field_index] = (other_field_index, other_table)
-
-        return relations
+                    key_columns.append(match.groups())
+        return key_columns
+    
+    def get_primary_key_column(self, cursor, table_name):
+        """
+        Returns the name of the primary key column for the given table
+        """
+        for column in self.get_indexes(cursor, table_name).iteritems():
+            if column[1]['primary_key']:
+                return column[0]
+        return None
 
     def get_indexes(self, cursor, table_name):
         """
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 930b1bb..3cadb66 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -428,6 +428,14 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation(self)
 
+    def check_constraints(self, table_names=None):
+        """
+        To check constraints, we set constraints to immediate. Then, when, we're done we must ensure they
+        are returned to deferred.
+        """
+        self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
+        self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
+
     def _valid_connection(self):
         return self.connection is not None
 
diff --git a/django/db/backends/postgresql_psycopg2/base.py b/django/db/backends/postgresql_psycopg2/base.py
index 6ed59a6..4136d4f 100644
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@@ -105,6 +105,14 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         self.introspection = DatabaseIntrospection(self)
         self.validation = BaseDatabaseValidation(self)
         self._pg_version = None
+    
+    def check_constraints(self, table_names=None):
+        """
+        To check constraints, we set constraints to immediate. Then, when, we're done we must ensure they
+        are returned to deferred.
+        """
+        self.cursor().execute('SET CONSTRAINTS ALL IMMEDIATE')
+        self.cursor().execute('SET CONSTRAINTS ALL DEFERRED')
 
     def _get_pg_version(self):
         if self._pg_version is None:
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 79c5ede..bc16d9a 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -206,6 +206,41 @@ class DatabaseWrapper(BaseDatabaseWrapper):
             connection_created.send(sender=self.__class__, connection=self)
         return self.connection.cursor(factory=SQLiteCursorWrapper)
 
+    def check_constraints(self, table_names=None):
+        """
+        Checks each table name in table-names for rows with invalid foreign key references. This method is
+        intended to be used in conjunction with `disable_constraint_checking()` and `enable_constraint_checking()`, to
+        determine if rows with invalid references were entered while constraint checks were off.
+
+        Raises an IntegrityError on the first invalid foreign key reference encountered (if any) and provides
+        detailed information about the invalid reference in the error message.
+
+        Backends can override this method if they can more directly apply constraint checking (e.g. via "SET CONSTRAINTS
+        ALL IMMEDIATE")
+        """
+        cursor = self.cursor()
+        if table_names is None:
+            table_names = self.introspection.get_table_list(cursor)
+        for table_name in table_names:
+            primary_key_column_name = self.introspection.get_primary_key_column(cursor, table_name)
+            if not primary_key_column_name:
+                continue
+            key_columns = self.introspection.get_key_columns(cursor, table_name)
+            for column_name, referenced_table_name, referenced_column_name in key_columns:
+                cursor.execute("""
+                    SELECT REFERRING.`%s`, REFERRING.`%s` FROM `%s` as REFERRING
+                    LEFT JOIN `%s` as REFERRED
+                    ON (REFERRING.`%s` = REFERRED.`%s`)
+                    WHERE REFERRING.`%s` IS NOT NULL
+                        AND REFERRED.`%s` IS NULL"""
+                    % (primary_key_column_name, column_name, table_name, referenced_table_name,
+                       column_name, referenced_column_name, column_name, referenced_column_name))
+                for bad_row in cursor.fetchall():
+                    raise utils.IntegrityError("The row in table '%s' with primary key '%s' has an invalid \
+foreign key: %s.%s contains a value '%s' that does not have a corresponding value in %s.%s."
+                                         % (table_name, bad_row[0], table_name, column_name, bad_row[1],
+                                            referenced_table_name, referenced_column_name))
+
     def close(self):
         # If database is in memory, closing the connection destroys the
         # database. To prevent accidental data loss, ignore close requests on
diff --git a/django/db/backends/sqlite3/introspection.py b/django/db/backends/sqlite3/introspection.py
index 5ee7b64..27de913 100644
--- a/django/db/backends/sqlite3/introspection.py
+++ b/django/db/backends/sqlite3/introspection.py
@@ -103,6 +103,35 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
 
         return relations
 
+    def get_key_columns(self, cursor, table_name):
+        """
+        Returns a list of (column_name, referenced_table_name, referenced_column_name) for all
+        key columns in given table.
+        """
+        key_columns = []
+
+        # Schema for this table
+        cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
+        results = cursor.fetchone()[0].strip()
+        results = results[results.index('(')+1:results.rindex(')')]
+
+        # Walk through and look for references to other tables. SQLite doesn't
+        # really have enforced references, but since it echoes out the SQL used
+        # to create the table we can look for REFERENCES statements used there.
+        for field_index, field_desc in enumerate(results.split(',')):
+            field_desc = field_desc.strip()
+            if field_desc.startswith("UNIQUE"):
+                continue
+
+            m = re.search('"(.*)".*references (.*) \(["|](.*)["|]\)', field_desc, re.I)
+            if not m:
+                continue
+
+            # This will append (column_name, referenced_table_name, referenced_column_name) to key_columns
+            key_columns.append(tuple([s.strip('"') for s in m.groups()]))
+
+        return key_columns
+        
     def get_indexes(self, cursor, table_name):
         """
         Returns a dictionary of fieldname -> infodict for the given table,
@@ -127,6 +156,21 @@ class DatabaseIntrospection(BaseDatabaseIntrospection):
             name = info[0][2] # seqno, cid, name
             indexes[name]['unique'] = True
         return indexes
+    
+    def get_primary_key_column(self, cursor, table_name):
+        """
+        Get the column name of the primary key for the given table.
+        """
+        # Don't use PRAGMA because that causes issues with some transactions
+        cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
+        results = cursor.fetchone()[0].strip()
+        results = results[results.index('(')+1:results.rindex(')')]
+        for field_desc in results.split(','):
+            field_desc = field_desc.strip()
+            m = re.search('"(.*)".*PRIMARY KEY$', field_desc)
+            if m:
+                return m.groups()[0]
+        return None
 
     def _table_info(self, cursor, name):
         cursor.execute('PRAGMA table_info(%s)' % self.connection.ops.quote_name(name))
diff --git a/django/db/backends/util.py b/django/db/backends/util.py
index 0766f87..e037a5a 100644
--- a/django/db/backends/util.py
+++ b/django/db/backends/util.py
@@ -29,6 +29,7 @@ class CursorWrapper(object):
 class CursorDebugWrapper(CursorWrapper):
 
     def execute(self, sql, params=()):
+        from django.db import connections
         start = time()
         try:
             return self.cursor.execute(sql, params)
@@ -36,10 +37,11 @@ class CursorDebugWrapper(CursorWrapper):
             stop = time()
             duration = stop - start
             sql = self.db.ops.last_executed_query(self.cursor, sql, params)
-            self.db.queries.append({
-                'sql': sql,
-                'time': "%.3f" % duration,
-            })
+            if not connections._ignore_num_queries:
+                self.db.queries.append({
+                    'sql': sql,
+                    'time': "%.3f" % duration,
+                })
             logger.debug('(%.3f) %s; args=%s' % (duration, sql, params),
                 extra={'duration':duration, 'sql':sql, 'params':params}
             )
@@ -143,4 +145,4 @@ def format_number(value, max_digits, decimal_places):
         context.prec = max_digits
         return u'%s' % str(value.quantize(decimal.Decimal(".1") ** decimal_places, context=context))
     else:
-        return u"%.*f" % (decimal_places, value)
+        return u"%.*f" % (decimal_places, value)
\ No newline at end of file
diff --git a/django/test/__init__.py b/django/test/__init__.py
index 68aea9a..04d985d 100644
--- a/django/test/__init__.py
+++ b/django/test/__init__.py
@@ -3,5 +3,5 @@ Django Unit Test and Doctest framework.
 """
 
 from django.test.client import Client, RequestFactory
-from django.test.testcases import TestCase, TransactionTestCase, skipIfDBFeature, skipUnlessDBFeature
+from django.test.testcases import TestCase, TransactionTestCase, skipIfDBFeature, skipUnlessDBFeature, ignore_num_queries
 from django.test.utils import Approximate
diff --git a/django/test/testcases.py b/django/test/testcases.py
index e767712..98c6887 100644
--- a/django/test/testcases.py
+++ b/django/test/testcases.py
@@ -23,6 +23,17 @@ from django.utils.encoding import smart_str
 __all__ = ('DocTestRunner', 'OutputChecker', 'TestCase', 'TransactionTestCase',
            'skipIfDBFeature', 'skipUnlessDBFeature')
 
+
+def ignore_num_queries(fn):
+    @wraps(fn)
+    def num_queries_ignored(*args, **kwargs):
+        connections._ignore_num_queries = True
+        try:
+            return fn(*args, **kwargs)
+        finally:
+            connections._ignore_num_queries = False
+    return num_queries_ignored
+
 normalize_long_ints = lambda s: re.sub(r'(?<![\w])(\d+)L(?![\w])', '\\1', s)
 normalize_decimals = lambda s: re.sub(r"Decimal\('(\d+(\.\d*)?)'\)", lambda m: "Decimal(\"%s\")" % m.groups()[0], s)
 
@@ -39,6 +50,8 @@ def to_list(value):
 
 real_commit = transaction.commit
 real_rollback = transaction.rollback
+real_commit_unless_managed = transaction.commit_unless_managed
+real_rollback_unless_managed = transaction.rollback_unless_managed
 real_enter_transaction_management = transaction.enter_transaction_management
 real_leave_transaction_management = transaction.leave_transaction_management
 real_managed = transaction.managed
@@ -46,9 +59,23 @@ real_managed = transaction.managed
 def nop(*args, **kwargs):
     return
 
+@ignore_num_queries
+def check_constraints(using=None):
+    """
+    Emulate the constraint check behavior that normally occurs when a transaction is rolled back or committed.
+    """
+    if using is None:
+        using = DEFAULT_DB_ALIAS
+    connection = connections[using]
+    # Don't check constraints if they have been manually disabled
+    if not connection.constraint_checking_disabled:
+        connection.check_constraints()
+
 def disable_transaction_methods():
-    transaction.commit = nop
+    transaction.commit = check_constraints
     transaction.rollback = nop
+    transaction.commit_unless_managed = check_constraints
+    transaction.rollback_unless_managed = nop
     transaction.enter_transaction_management = nop
     transaction.leave_transaction_management = nop
     transaction.managed = nop
@@ -56,6 +83,8 @@ def disable_transaction_methods():
 def restore_transaction_methods():
     transaction.commit = real_commit
     transaction.rollback = real_rollback
+    transaction.commit_unless_managed = real_commit_unless_managed
+    transaction.rollback_unless_managed = real_rollback_unless_managed
     transaction.enter_transaction_management = real_enter_transaction_management
     transaction.leave_transaction_management = real_leave_transaction_management
     transaction.managed = real_managed
@@ -580,6 +609,9 @@ class TestCase(TransactionTestCase):
 
         from django.contrib.sites.models import Site
         Site.objects.clear_cache()
+        
+        from django.contrib.contenttypes.models import ContentType
+        ContentType.objects.clear_cache()
 
         for db in databases:
             if hasattr(self, 'fixtures'):
diff --git a/docs/ref/databases.txt b/docs/ref/databases.txt
index 2f55b9c..5a2042a 100644
--- a/docs/ref/databases.txt
+++ b/docs/ref/databases.txt
@@ -142,6 +142,18 @@ currently the only engine that supports full-text indexing and searching.
 The InnoDB_ engine is fully transactional and supports foreign key references
 and is probably the best choice at this point in time.
 
+.. versionchanged:: 1.4
+
+In previous versions of Django, fixtures with forward references (i.e.
+relations to rows that have not yet been inserted into the database) would fail
+to load when using the InnoDB storage engine. This was due to the fact that InnoDB
+deviates from the SQL standard by checking foreign key constraints immediately
+instead of deferring the check until the transaction is committed. This
+problem has been resolved in Django 1.4. Fixture data is now loaded with foreign key
+checks turned off; foreign key checks are then re-enabled when the data has
+finished loading, at which point the entire table is checked for invalid foreign
+key references and an `IntegrityError` is raised if any are found.
+
 .. _storage engines: http://dev.mysql.com/doc/refman/5.5/en/storage-engines.html
 .. _MyISAM: http://dev.mysql.com/doc/refman/5.5/en/myisam-storage-engine.html
 .. _InnoDB: http://dev.mysql.com/doc/refman/5.5/en/innodb.html
diff --git a/tests/modeltests/serializers/tests.py b/tests/modeltests/serializers/tests.py
index 4a7e0a2..def0254 100644
--- a/tests/modeltests/serializers/tests.py
+++ b/tests/modeltests/serializers/tests.py
@@ -1,3 +1,7 @@
+# This is necessary in Python 2.5 to enable the with statement, in 2.6
+# and up it is no longer necessary.
+from __future__ import with_statement
+
 # -*- coding: utf-8 -*-
 from datetime import datetime
 from StringIO import StringIO
@@ -5,7 +9,7 @@ from xml.dom import minidom
 
 from django.conf import settings
 from django.core import serializers
-from django.db import transaction
+from django.db import transaction, connection
 from django.test import TestCase, TransactionTestCase, Approximate
 from django.utils import simplejson, unittest
 
@@ -252,8 +256,9 @@ class SerializersTransactionTestBase(object):
         transaction.enter_transaction_management()
         transaction.managed(True)
         objs = serializers.deserialize(self.serializer_name, self.fwd_ref_str)
-        for obj in objs:
-            obj.save()
+        with connection.constraint_checks_disabled():
+            for obj in objs:
+                obj.save()
         transaction.commit()
         transaction.leave_transaction_management()
 
diff --git a/tests/regressiontests/backends/tests.py b/tests/regressiontests/backends/tests.py
index 29db6a7..be5d6f4 100644
--- a/tests/regressiontests/backends/tests.py
+++ b/tests/regressiontests/backends/tests.py
@@ -1,10 +1,11 @@
 # -*- coding: utf-8 -*-
 # Unit and doctests for specific database backends.
+from __future__ import with_statement
 import datetime
 
 from django.conf import settings
 from django.core.management.color import no_style
-from django.db import backend, connection, connections, DEFAULT_DB_ALIAS, IntegrityError
+from django.db import backend, connection, connections, DEFAULT_DB_ALIAS, IntegrityError, transaction
 from django.db.backends.signals import connection_created
 from django.db.backends.postgresql_psycopg2 import version as pg_version
 from django.test import TestCase, skipUnlessDBFeature, TransactionTestCase
@@ -328,7 +329,8 @@ class FkConstraintsTests(TransactionTestCase):
         try:
             a.save()
         except IntegrityError:
-            pass
+            return
+        self.skipTest("This backend does not support integrity checks.")
 
     def test_integrity_checks_on_update(self):
         """
@@ -343,4 +345,63 @@ class FkConstraintsTests(TransactionTestCase):
         try:
             a.save()
         except IntegrityError:
-            pass
+            return
+        self.skipTest("This backend does not support integrity checks.")
+    
+    def test_disable_constraint_checks_manually(self):
+        """
+        When constraint checks are disabled, should be able to write bad data without IntegrityErrors. Also,
+        should set disabled flag.
+        """
+        with transaction.commit_manually():
+            # Create an Article.
+            models.Article.objects.create(headline="Test article", pub_date=datetime.datetime(2010, 9, 4), reporter=self.r)
+            # Retrive it from the DB
+            a = models.Article.objects.get(headline="Test article")
+            a.reporter_id = 30
+            try:
+                connection.disable_constraint_checking()
+                self.assertTrue(connection.constraint_checking_disabled)
+                a.save()
+                connection.enable_constraint_checking()
+            except IntegrityError:
+                self.fail("IntegrityError should not have occurred.")
+            finally:
+                transaction.rollback()
+    
+    def test_disable_constraint_checks_context_manager(self):
+        """
+        When constraint checks are disabled (using context manager), should be able to write bad data without IntegrityErrors.
+        """
+        with transaction.commit_manually():
+            # Create an Article.
+            models.Article.objects.create(headline="Test article", pub_date=datetime.datetime(2010, 9, 4), reporter=self.r)
+            # Retrive it from the DB
+            a = models.Article.objects.get(headline="Test article")
+            a.reporter_id = 30
+            try:
+                with connection.constraint_checks_disabled():
+                    self.assertTrue(connection.constraint_checking_disabled)
+                    a.save()
+            except IntegrityError:
+                self.fail("IntegrityError should not have occurred.")
+            finally:
+                transaction.rollback()
+    
+    def test_check_constraints(self):
+        """
+        Constraint checks should raise an IntegrityError when bad data is in the DB.
+        """
+        with transaction.commit_manually():
+            # Create an Article.
+            models.Article.objects.create(headline="Test article", pub_date=datetime.datetime(2010, 9, 4), reporter=self.r)
+            # Retrive it from the DB
+            a = models.Article.objects.get(headline="Test article")
+            a.reporter_id = 30
+            try:
+                with connection.constraint_checks_disabled():
+                    a.save()
+                    with self.assertRaises(IntegrityError):
+                        connection.check_constraints()
+            finally:
+                transaction.rollback()
diff --git a/tests/regressiontests/comment_tests/tests/templatetag_tests.py b/tests/regressiontests/comment_tests/tests/templatetag_tests.py
index 0ee34ac..835017c 100644
--- a/tests/regressiontests/comment_tests/tests/templatetag_tests.py
+++ b/tests/regressiontests/comment_tests/tests/templatetag_tests.py
@@ -42,7 +42,9 @@ class CommentTemplateTagTests(CommentTestCase):
     def testRenderCommentFormFromObjectWithQueryCount(self):
         def test():
             self.testRenderCommentFormFromObject()
-        self.assertNumQueries(1, test)
+        # 1 to select object
+        # 1 to get the contenttype
+        self.assertNumQueries(2, test)
 
     def testGetCommentCount(self, tag=None):
         self.createSomeComments()
diff --git a/tests/regressiontests/fixtures_regress/fixtures/forward_ref.json b/tests/regressiontests/fixtures_regress/fixtures/forward_ref.json
new file mode 100644
index 0000000..237b076
--- /dev/null
+++ b/tests/regressiontests/fixtures_regress/fixtures/forward_ref.json
@@ -0,0 +1,17 @@
+[
+    {
+        "pk": 1,
+        "model": "fixtures_regress.book",
+        "fields": {
+            "name": "Cryptonomicon",
+            "author": 4
+        }
+    },
+    {
+        "pk": "4",
+        "model": "fixtures_regress.person",
+        "fields": {
+            "name": "Neal Stephenson"
+        }
+    }
+]
\ No newline at end of file
diff --git a/tests/regressiontests/fixtures_regress/fixtures/forward_ref_bad_data.json b/tests/regressiontests/fixtures_regress/fixtures/forward_ref_bad_data.json
new file mode 100644
index 0000000..3a3fb64
--- /dev/null
+++ b/tests/regressiontests/fixtures_regress/fixtures/forward_ref_bad_data.json
@@ -0,0 +1,17 @@
+[
+    {
+        "pk": 1,
+        "model": "fixtures_regress.book",
+        "fields": {
+            "name": "Cryptonomicon",
+            "author": 3
+        }
+    },
+    {
+        "pk": "4",
+        "model": "fixtures_regress.person",
+        "fields": {
+            "name": "Neal Stephenson"
+        }
+    }
+]
\ No newline at end of file
diff --git a/tests/regressiontests/fixtures_regress/tests.py b/tests/regressiontests/fixtures_regress/tests.py
index a565ec9..344bc04 100644
--- a/tests/regressiontests/fixtures_regress/tests.py
+++ b/tests/regressiontests/fixtures_regress/tests.py
@@ -361,6 +361,35 @@ class TestFixtures(TestCase):
             """[{"pk": %d, "model": "fixtures_regress.widget", "fields": {"name": "grommet"}}]"""
             % widget.pk
             )
+    
+    def test_loaddata_works_when_fixture_has_forward_refs(self):
+        """
+        Regression for #3615 - Forward references cause fixtures not to load in MySQL (InnoDB)
+        """
+        management.call_command(
+            'loaddata',
+            'forward_ref.json',
+            verbosity=0,
+            commit=False
+        )
+        self.assertEqual(Book.objects.all()[0].id, 1)
+        self.assertEqual(Person.objects.all()[0].id, 4)
+    
+    def test_loaddata_raises_error_when_fixture_has_invalid_foreign_key(self):
+        """
+        Regression for #3615 - Ensure data with nonexistent child key references raises error
+        """
+        stderr = StringIO()
+        management.call_command(
+            'loaddata',
+            'forward_ref_bad_data.json',
+            verbosity=0,
+            commit=False,
+            stderr=stderr,
+        )
+        self.assertTrue(
+            stderr.getvalue().startswith('Problem installing fixture')
+        )
 
 
 class NaturalKeyFixtureTests(TestCase):
diff --git a/tests/regressiontests/introspection/tests.py b/tests/regressiontests/introspection/tests.py
index 4f5fb09..a7c5bf2 100644
--- a/tests/regressiontests/introspection/tests.py
+++ b/tests/regressiontests/introspection/tests.py
@@ -95,6 +95,16 @@ class IntrospectionTests(TestCase):
             # That's {field_index: (field_index_other_table, other_table)}
             self.assertEqual(relations, {3: (0, Reporter._meta.db_table)})
 
+    def test_get_key_columns(self):
+        cursor = connection.cursor()
+        key_columns = connection.introspection.get_key_columns(cursor, Article._meta.db_table)
+        self.assertEqual(key_columns, [(u'reporter_id', Reporter._meta.db_table, u'id')])
+    
+    def test_get_primary_key_column(self):
+        cursor = connection.cursor()
+        primary_key_column = connection.introspection.get_primary_key_column(cursor, Article._meta.db_table)
+        self.assertEqual(primary_key_column, u'id')
+
     def test_get_indexes(self):
         cursor = connection.cursor()
         indexes = connection.introspection.get_indexes(cursor, Article._meta.db_table)
diff --git a/tests/regressiontests/serializers_regress/tests.py b/tests/regressiontests/serializers_regress/tests.py
index cd2ce3c..bb6f598 100644
--- a/tests/regressiontests/serializers_regress/tests.py
+++ b/tests/regressiontests/serializers_regress/tests.py
@@ -6,6 +6,8 @@ test case that is capable of testing the capabilities of
 the serializers. This includes all valid data values, plus
 forward, backwards and self references.
 """
+# This is necessary in Python 2.5 to enable the with statement, in 2.6
+# and up it is no longer necessary.
 from __future__ import with_statement
 
 import datetime
@@ -382,7 +384,8 @@ def serializerTest(format, self):
     objects = []
     instance_count = {}
     for (func, pk, klass, datum) in test_data:
-        objects.extend(func[0](pk, klass, datum))
+        with connection.constraint_checks_disabled():
+            objects.extend(func[0](pk, klass, datum))
 
     # Get a count of the number of objects created for each class
     for klass in instance_count:
diff --git a/tests/regressiontests/test_utils/models.py b/tests/regressiontests/test_utils/models.py
index 4da7a07..7a7a94e 100644
--- a/tests/regressiontests/test_utils/models.py
+++ b/tests/regressiontests/test_utils/models.py
@@ -3,3 +3,13 @@ from django.db import models
 
 class Person(models.Model):
     name = models.CharField(max_length=100)
+
+class Pet(models.Model):
+    name = models.CharField(max_length=100)
+    owner = models.ForeignKey(Person)
+
+    def __unicode__(self):
+        return self.name
+
+    class Meta:
+        ordering = ('name',)
diff --git a/tests/regressiontests/test_utils/tests.py b/tests/regressiontests/test_utils/tests.py
index a35b0bc..6e26b24 100644
--- a/tests/regressiontests/test_utils/tests.py
+++ b/tests/regressiontests/test_utils/tests.py
@@ -1,9 +1,10 @@
 from __future__ import with_statement
 
-from django.test import TestCase, skipUnlessDBFeature
+from django.test import TestCase, skipUnlessDBFeature, ignore_num_queries
 from django.utils.unittest import skip
+from django.db import IntegrityError
 
-from models import Person
+from models import Person, Pet
 
 
 class SkippingTestCase(TestCase):
@@ -47,6 +48,15 @@ class AssertNumQueriesTests(TestCase):
             self.client.get("/test_utils/get_person/%s/" % person.pk)
             self.client.get("/test_utils/get_person/%s/" % person.pk)
         self.assertNumQueries(2, test_func)
+    
+    def test_assert_num_queries_ignore_decorator(self):
+        person = Person.objects.create(name='test')
+        
+        @ignore_num_queries
+        def test_func():
+            self.client.get("/test_utils/get_person/%s/" % person.pk)
+            self.client.get("/test_utils/get_person/%s/" % person.pk)
+        self.assertNumQueries(0, test_func)
 
 class AssertNumQueriesContextManagerTests(TestCase):
     urls = 'regressiontests.test_utils.urls'
@@ -86,6 +96,17 @@ class AssertNumQueriesContextManagerTests(TestCase):
             self.client.get("/test_utils/get_person/%s/" % person.pk)
 
 
+class TransactionPatchingTests(TestCase):
+    def test_bad_data_should_raise_data_integrity_error(self):
+        """
+        Ensure bad data cannot be saved to DB during tests.
+        """
+        bill = Person.objects.create(name="Bill")
+        dog = Pet.objects.create(name="Spot", owner=bill)
+        dog.owner_id = 20 # Does not exist
+        with self.assertRaises(IntegrityError):
+            dog.save()
+
 class SaveRestoreWarningState(TestCase):
     def test_save_restore_warnings_state(self):
         """
