Support of restart_identity on truncate operation

docs/source/deletion.rst

@@ -48,3 +48,28 @@ By default, Postgres will raise an error if any other table is referencing one o
    MyModel.objects.truncate(cascade=True)
    print(MyModel1.objects.count()) # zero records left
    print(MyModel2.objects.count()) # zero records left
+
+
+Restart identity
+****************
+
+If specified, any sequences on the table will be restarted.
+
+.. code-block:: python
+
+   from django.db import models
+   from psqlextra.models import PostgresModel
+
+   class MyModel(PostgresModel):
+      pass
+
+   mymodel = MyModel.objects.create()
+   assert mymodel.id == 1
+
+   MyModel.objects.truncate(restart_identity=True) # table is empty after this
+   print(MyModel.objects.count()) # zero records left
+
+   # Create a new row, it should get ID 1 again because
+   # the sequence got restarted.
+   mymodel = MyModel.objects.create()
+   assert mymodel.id == 1

psqlextra/manager/manager.py

@@ -37,7 +37,10 @@ def __init__(self, *args, **kwargs):
             )
 
     def truncate(
-        self, cascade: bool = False, using: Optional[str] = None
+        self,
+        cascade: bool = False,
+        restart_identity: bool = False,
+        using: Optional[str] = None,
     ) -> None:
         """Truncates this model/table using the TRUNCATE statement.
 
@@ -51,14 +54,19 @@ def truncate(
                 False, an error will be raised if there
                 are rows in other tables referencing
                 the rows you're trying to delete.
+            restart_identity:
+                Automatically restart sequences owned by
+                columns of the truncated table(s).
         """
 
         connection = connections[using or "default"]
         table_name = connection.ops.quote_name(self.model._meta.db_table)
 
         with connection.cursor() as cursor:
-            sql = "TRUNCATE TABLE %s" % table_name
+            sql = f"TRUNCATE TABLE {table_name}"
             if cascade:
                 sql += " CASCADE"
+            if restart_identity:
+                sql += " RESTART IDENTITY"
 
             cursor.execute(sql)