From 0bf2ad5b6730638d5c4a3f75e5329d4564116702 Mon Sep 17 00:00:00 2001
From: Ross Lawley <ross.lawley@gmail.com>
Date: Fri, 24 Aug 2012 09:30:08 +0100
Subject: [PATCH] Use pk in ReferenceField fixes  MongoEngine/mongoengine#85

---
 mongoengine/fields.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mongoengine/fields.py b/mongoengine/fields.py
index eb579606..a2d862de 100644
--- a/mongoengine/fields.py
+++ b/mongoengine/fields.py
@@ -774,7 +774,7 @@ class ReferenceField(BaseField):
 
         if isinstance(document, Document):
             # We need the id from the saved object to create the DBRef
-            id_ = document.id
+            id_ = document.pk
             if id_ is None:
                 self.error('You can only reference documents once they have'
                            ' been saved to the database')