Ticket #2192: datefield_unique.2.diff

django/db/models/fields/__init__.py

@@ -411 +411 @@
     def get_db_prep_lookup(self, lookup_type, value):
         if lookup_type == 'range':
             value = [str(v) for v in value]
-        elif lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte', 'ne'):
+        elif type(value) is not str and lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte', 'ne'):
             value = value.strftime('%Y-%m-%d')
         else:
             value = str(value)