Return row count for bulk inserts.

Note: postgres will continue to return a cursor iterator over the
inserted primary-keys by default. To disable this and retrieve a
rowcount instead, specify an empty returning, e.g. `.returning()`.

CHANGELOG.md

@@ -7,6 +7,13 @@ https://github.com/coleifer/peewee/releases
 
 ## master
 
+* Bulk insert (`insert_many()` and `insert_from()`) will now return the row
+  count instead of the last insert ID. If you are using Postgres, peewee will
+  continue to return a cursor that provides an iterator over the newly-inserted
+  primary-key values by default. This behavior is being retained by default for
+  compatibility. Postgres users can simply specify an empty `returning()` call
+  to disable the cursor and retrieve the rowcount instead.
+
 [View commits](https://github.com/coleifer/peewee/compare/3.11.2...master)
 
 ## 3.11.2

peewee.py

@@ -2627,6 +2627,8 @@ class Insert(_WriteQuery):
     def handle_result(self, database, cursor):
         if self._return_cursor:
             return cursor
+        if self._query_type != Insert.SIMPLE and not self._returning:
+            return database.rows_affected(cursor)
         return database.last_insert_id(cursor, self._query_type)
 
 
@@ -3651,7 +3653,7 @@ class PostgresqlDatabase(Database):
 
     def last_insert_id(self, cursor, query_type=None):
         try:
-            return cursor if query_type else cursor[0][0]
+            return cursor if query_type != Insert.SIMPLE else cursor[0][0]
         except (IndexError, KeyError, TypeError):
             pass
 

tests/models.py

@@ -369,6 +369,33 @@ class TestModelAPIs(ModelTestCase):
         self.assertEqual(list(sorted(CPK.select().tuples())), [
             ('k1', 1, 10), ('k2', 2, 2), ('k3', 3, 30)])
 
+    @requires_models(User)
+    def test_insert_rowcount(self):
+        User.create(username='u0')  # Ensure that last insert ID != rowcount.
+
+        iq = User.insert_many([(u,) for u in ('u1', 'u2', 'u3')])
+        if IS_POSTGRESQL:
+            iq = iq.returning()
+        self.assertEqual(iq.execute(), 3)
+
+        # Now explicitly specify empty returning() for all DBs.
+        iq = User.insert_many([(u,) for u in ('u4', 'u5')]).returning()
+        self.assertEqual(iq.execute(), 2)
+
+        query = (User
+                 .select(User.username.concat('-x'))
+                 .where(User.username.in_(['u1', 'u2'])))
+        iq = User.insert_from(query, ['username'])
+        if IS_POSTGRESQL:
+            iq = iq.returning()
+        self.assertEqual(iq.execute(), 2)
+
+        query = (User
+                 .select(User.username.concat('-y'))
+                 .where(User.username.in_(['u3', 'u4'])))
+        iq = User.insert_from(query, ['username']).returning()
+        self.assertEqual(iq.execute(), 2)
+
     @requires_models(User, Tweet)
     def test_get_shortcut(self):
         huey = self.add_user('huey')