Ticket #4944: 4944.diff

docs/model-api.txt

@@ -663 +663 @@
 If ``True``, this field must be unique throughout the table.
 
 This is enforced at the database level and at the Django admin-form level.
+If you try to add a second instance with the same field value, an 
+IntegrityError will be raised by ``save()``.
 
 ``unique_for_date``
 ~~~~~~~~~~~~~~~~~~~