diff --git a/gluon/dal.py b/gluon/dal.py
index 638afe99..2a7f769a 100644
--- a/gluon/dal.py
+++ b/gluon/dal.py
@@ -1359,8 +1359,9 @@ class BaseAdapter(ConnectionPool):
                 return table._on_insert_error(table,fields,e)
             raise e
         if hasattr(table,'_primarykey'):
-            return dict([(k[0].name, k[1]) for k in fields \
-                             if k[0].name in table._primarykey])
+            mydict = dict([(k[0].name, k[1]) for k in fields if k[0].name in table._primarykey])
+            if mydict != {}:
+                return mydict
         id = self.lastrowid(table)
         if not isinstance(id, (int, long)):
             return id