From 200e52bab50906761fa09b8a34f0cac5ddec335e Mon Sep 17 00:00:00 2001
From: Ross Lawley <ross.lawley@gmail.com>
Date: Tue, 20 Aug 2013 18:44:12 +0000
Subject: [PATCH] Added documentation about abstract meta

Refs #438
---
 docs/guide/defining-documents.rst | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/docs/guide/defining-documents.rst b/docs/guide/defining-documents.rst
index 407fbdac..ba1af333 100644
--- a/docs/guide/defining-documents.rst
+++ b/docs/guide/defining-documents.rst
@@ -689,7 +689,6 @@ document.::
 .. note:: From 0.8 onwards you must declare :attr:`allow_inheritance` defaults
           to False, meaning you must set it to True to use inheritance.
 
-
 Working with existing data
 --------------------------
 As MongoEngine no longer defaults to needing :attr:`_cls` you can quickly and
@@ -709,3 +708,25 @@ defining all possible field types.
 
 If you use :class:`~mongoengine.Document` and the database contains data that
 isn't defined then that data will be stored in the `document._data` dictionary.
+
+Abstract classes
+================
+
+If you want to add some extra functionality to a group of Document classes but
+you don't need or want the overhead of inheritance you can use the
+:attr:`abstract` attribute of :attr:`-mongoengine.Document.meta`.
+This won't turn on :ref:`document-inheritance` but will allow you to keep your
+code DRY::
+
+        class BaseDocument(Document):
+            meta = {
+                'abstract': True,
+            }
+            def check_permissions(self):
+                ...
+
+        class User(BaseDocument):
+           ...
+
+Now the User class will have access to the inherited `check_permissions` method
+and won't store any of the extra `_cls` information.