diff --git a/datalite/mass_actions.py b/datalite/mass_actions.py
index 3da743e..08f4c06 100644
--- a/datalite/mass_actions.py
+++ b/datalite/mass_actions.py
@@ -65,8 +65,10 @@ def _mass_insert(objects: Union[List[T], Tuple[T]], db_name: str, protect_memory
     sql_queries = []
     first_index: int = 0
     table_name = objects[0].__class__.__name__.lower()
-    for obj in objects:
+
+    for i, obj in enumerate(objects):
         kv_pairs = asdict(obj).items()
+        setattr(obj, "obj_id", first_index + i + 1)
         sql_queries.append(f"INSERT INTO {table_name}(" +
                            f"{', '.join(item[0] for item in kv_pairs)})" +
                            f" VALUES ({', '.join(_convert_sql_format(item[1]) for item in kv_pairs)});")
@@ -81,8 +83,6 @@ def _mass_insert(objects: Union[List[T], Tuple[T]], db_name: str, protect_memory
             cur.executescript("BEGIN TRANSACTION;\n" + '\n'.join(sql_queries) + '\nEND TRANSACTION;')
         except sql.IntegrityError:
             raise ConstraintFailedError
-    for i, obj in enumerate(objects):
-        setattr(obj, "obj_id", first_index + i + 1)
 
 
 def create_many(objects: Union[List[T], Tuple[T]], protect_memory: bool = True) -> None:
diff --git a/test/main_tests.py b/test/main_tests.py
index d86d138..578c729 100644
--- a/test/main_tests.py
+++ b/test/main_tests.py
@@ -199,16 +199,23 @@ class DatabaseMassInsert(unittest.TestCase):
     def setUp(self) -> None:
         self.objs = [MassCommit(f'cat + {i}') for i in range(30)]
 
+
     def testMassCreate(self):
+        with connect('other.db') as con:
+            cur = con.cursor()
+            cur.execute(f'CREATE TABLE IF NOT EXISTS MASSCOMMIT (obj_id, str_)')
+
+        start_tup = fetch_all(MassCommit)
         create_many(self.objs, protect_memory=False)
         _objs = fetch_all(MassCommit)
-        self.assertEqual(_objs, tuple(self.objs))
+        self.assertEqual(_objs, start_tup + tuple(self.objs))
 
     def testMassCopy(self):
-        copy_many(self.objs, 'other.db', False)
         setattr(MassCommit, 'db_path', 'other.db')
+        start_tup = fetch_all(MassCommit)
+        copy_many(self.objs, 'other.db', False)
         tup = fetch_all(MassCommit)
-        self.assertEqual(tup, tuple(self.objs))
+        self.assertEqual(tup, start_tup + tuple(self.objs))
 
     def tearDown(self) -> None:
         [obj.remove_entry() for obj in self.objs]