diff --git a/tests/_utils/setup.sql b/tests/_utils/setup.sql
index c883b8bf3a9f..94c797335d7f 100644
--- a/tests/_utils/setup.sql
+++ b/tests/_utils/setup.sql
@@ -571,3 +571,22 @@ CREATE TABLE `bulk_create_relatedmodel_bigautofieldmodel` (
   KEY (`relatedmodel_id`),
   KEY (`bigautofieldmodel_id`)
 );
+
+-- backends
+CREATE TABLE `backends_verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz_person` (
+  `verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz_id` BIGINT NOT NULL,
+  `person_id` BIGINT NOT NULL,
+  SHARD KEY (`verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz_id`),
+  UNIQUE KEY (`verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz_id`, `person_id`),
+  KEY (`verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz_id`),
+  KEY (`person_id`)
+);
+
+CREATE TABLE `backends_object_object` (
+  `from_object_id` BIGINT NOT NULL,
+  `to_object_id` BIGINT NOT NULL,
+  SHARD KEY (`from_object_id`),
+  UNIQUE KEY (`from_object_id`, `to_object_id`),
+  KEY (`from_object_id`),
+  KEY (`to_object_id`)
+);
diff --git a/tests/backends/models.py b/tests/backends/models.py
index 99e9e86f44d2..4aa88da9a768 100644
--- a/tests/backends/models.py
+++ b/tests/backends/models.py
@@ -40,10 +40,22 @@ class VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ(models.Model):
         max_length=100
     )
     m2m_also_quite_long_zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz = (
-        models.ManyToManyField(Person, blank=True)
+        models.ManyToManyField(Person, blank=True,
+                               through="VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZPerson")
     )
 
 
+class VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZPerson(models.Model):
+    verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz = models.ForeignKey(
+        VeryLongModelNameZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ, on_delete=models.CASCADE
+        )
+    person = models.ForeignKey(Person, on_delete=models.CASCADE)
+
+    class Meta:
+        unique_together = (('verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz', 'person'),)
+        db_table = "backends_verylongmodelnamezzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz_person"
+
+
 class Tag(models.Model):
     name = models.CharField(max_length=30)
     content_type = models.ForeignKey(
@@ -102,14 +114,23 @@ def __str__(self):
 
 class Object(models.Model):
     related_objects = models.ManyToManyField(
-        "self", db_constraint=False, symmetrical=False
-    )
+        "self", symmetrical=False, through="ObjectFriend"
+        )
     obj_ref = models.ForeignKey("ObjectReference", models.CASCADE, null=True)
 
     def __str__(self):
         return str(self.id)
 
 
+class ObjectFriend(models.Model):
+    from_object = models.ForeignKey(Object, on_delete=models.CASCADE, related_name="from_object")
+    to_object = models.ForeignKey(Object, on_delete=models.CASCADE, related_name="to_object")
+
+    class Meta:
+        unique_together = (('from_object', 'to_object'),)
+        db_table = "backends_object_object"
+
+
 class ObjectReference(models.Model):
     obj = models.ForeignKey(Object, models.CASCADE, db_constraint=False)
 
@@ -118,12 +139,12 @@ def __str__(self):
 
 
 class ObjectSelfReference(models.Model):
-    key = models.CharField(max_length=3, unique=True)
+    key = models.CharField(max_length=3, primary_key=True)
     obj = models.ForeignKey("ObjectSelfReference", models.SET_NULL, null=True)
 
 
 class CircularA(models.Model):
-    key = models.CharField(max_length=3, unique=True)
+    key = models.CharField(max_length=3, primary_key=True)
     obj = models.ForeignKey("CircularB", models.SET_NULL, null=True)
 
     def natural_key(self):
@@ -131,7 +152,7 @@ def natural_key(self):
 
 
 class CircularB(models.Model):
-    key = models.CharField(max_length=3, unique=True)
+    key = models.CharField(max_length=3, primary_key=True)
     obj = models.ForeignKey("CircularA", models.SET_NULL, null=True)
 
     def natural_key(self):
@@ -143,7 +164,7 @@ class RawData(models.Model):
 
 
 class Author(models.Model):
-    name = models.CharField(max_length=255, unique=True)
+    name = models.CharField(max_length=255, primary_key=True)
 
 
 class Book(models.Model):
diff --git a/tests/backends/test_utils.py b/tests/backends/test_utils.py
index 03d4b036fdfd..aad82bfc597b 100644
--- a/tests/backends/test_utils.py
+++ b/tests/backends/test_utils.py
@@ -2,6 +2,7 @@
 from decimal import Decimal, Rounded
 
 from django.db import NotSupportedError, connection
+from django.db.utils import OperationalError
 from django.db.backends.utils import (
     format_number,
     split_identifier,
@@ -94,6 +95,12 @@ class CursorWrapperTests(TransactionTestCase):
     available_apps = []
 
     def _test_procedure(self, procedure_sql, params, param_types, kparams=None):
+        # make sure procedure is not already defined
+        try:
+            with connection.schema_editor() as editor:
+                editor.remove_procedure("test_procedure", param_types)
+        except OperationalError:
+            pass
         with connection.cursor() as cursor:
             cursor.execute(procedure_sql)
         # Use a new cursor because in MySQL a procedure can't be used in the