Supporting refining of existing results generators.

dictorm/dictorm.py

@@ -337,10 +337,8 @@ def _execute_once(self):
         """
         if not self.executed:
             self.executed = True
-            if not self.refined:
-                # Use the default order by
-                self.refine(order_by=self.order_by)
-            self.curs.execute(self.query.query, self.query.wheres)
+            query = self.query.build()
+            self.curs.execute(query, self.query.wheres)
 
 
     # for python 2.7
@@ -357,11 +355,13 @@ def __len__(self):
 
     def refine(self, **kw):
         """
-        Refine the results of this generator before the results are fetched.
+        Get a new ResultsGenerator built from this generator's properties, but
+        now with the additional properties provided as arguments.
+
+        See Query.refine for supported refinements.
         """
         self.query.refine(**kw)
-        self.query.build()
-        return self
+        return ResultsGenerator(self.query)
 
 
 

dictorm/test.py

@@ -826,7 +826,7 @@ def test_real(self):
         self.assertEqual(_remove_refs(car_owners), _remove_refs([milton, peter]))
 
 
-    def test_refine(self):
+    def test_refine_order_by(self):
         """
         A result set can be refined using order by.  A reference can be refined
         using the same technique.
@@ -861,7 +861,7 @@ def test_refine(self):
         self.assertEqual(list(all_subordinates.refine(name='Alice')), [alice,])
 
 
-    def test_refine2(self):
+    def test_refine_offset_limit(self):
         """
         A result set can be refined using an offset and limit.
         """
@@ -872,14 +872,23 @@ def test_refine2(self):
         abe = Person(name='Abe').flush()
         gus = Person(name='Gus').flush()
 
-        self.assertEqual(list(Person.get_where()), [bob, aly, tom, abe, gus])
+        persons = Person.get_where()
+        self.assertEqual(list(persons), [bob, aly, tom, abe, gus])
+        self.assertEqual(list(persons), [bob, aly, tom, abe, gus])
+
         # Using limit and offset, but in such a way that it returns everything
         if self.db.kind == 'postgresql':
-            self.assertEqual(list(Person.get_where().refine(limit='ALL', offset=0)),
+            self.assertEqual(list(persons.refine(limit='ALL', offset=0)),
                     [bob, aly, tom, abe, gus])
 
-        self.assertEqual(list(Person.get_where().refine(limit=2)), [bob, aly])
-        self.assertEqual(list(Person.get_where().refine(limit=2, offset=3)), [abe, gus])
+        # Single refine
+        limited = persons.refine(limit=2)
+        self.assertEqual(list(limited), [bob, aly])
+        self.assertEqual(list(limited), [bob, aly])
+
+        self.assertEqual(list(limited.refine(offset=3)), [abe, gus])
+        # Multiple refinings
+        self.assertEqual(list(persons.refine(limit=2).refine(offset=2)), [tom, abe])
 
 
     def test_onetoone_cache(self):