Index: model-api.txt
===================================================================
--- model-api.txt	(revision 8227)
+++ model-api.txt	(working copy)
@@ -681,6 +681,11 @@
 you try to save a model with a duplicate value in a ``unique`` field, a
 ``django.db.IntegrityError`` will be raised by the model's ``save()`` method.
 
+In MySQL, declaring a CharField as unique will change the collation of
+the field, as it becomes necessary to declare the field as BINARY to
+support keys that only differ in case. If that is undesired, you can
+manually alter the table to drop this binary attribute.
+
 ``unique_for_date``
 ~~~~~~~~~~~~~~~~~~~