Fix for reflection when no primary key present.

playhouse/reflection.py

@@ -715,7 +715,11 @@ class Meta:
             # Fix models with multi-column primary keys.
             composite_key = False
             if len(primary_keys) == 0:
-                primary_keys = columns.keys()
+                if 'id' not in columns:
+                    Meta.primary_key = False
+                else:
+                    primary_keys = columns.keys()
+
             if len(primary_keys) > 1:
                 Meta.primary_key = CompositeKey(*[
                     field.name for col, field in columns.items()

tests/reflection.py

@@ -69,6 +69,12 @@ class Nugget(TestModel):
     category = CharField()
 
 
+class NoPK(TestModel):
+    data = CharField()
+    class Meta:
+        primary_key = False
+
+
 class BaseReflectionTestCase(ModelTestCase):
     def setUp(self):
         super(BaseReflectionTestCase, self).setUp()
@@ -444,6 +450,16 @@ def test_get_field(self):
                                 '%s not in %s' % (actual, fields))
 
 
+class TestReflectNoPK(BaseReflectionTestCase):
+    requires = [NoPK]
+
+    def test_no_pk(self):
+        models = self.introspector.generate_models()
+        NoPK = models['no_pk']
+        self.assertEqual(NoPK._meta.sorted_field_names, ['data'])
+        self.assertTrue(NoPK._meta.primary_key is False)
+
+
 class EventLog(TestModel):
     data = CharField(constraints=[SQL('DEFAULT \'\'')])
     timestamp = DateTimeField(constraints=[SQL('DEFAULT current_timestamp')])