diff --git a/django/core/db/backends/ado_mssql.py b/django/core/db/backends/ado_mssql.py
index a13ac834b1..9ea0d5456d 100644
--- a/django/core/db/backends/ado_mssql.py
+++ b/django/core/db/backends/ado_mssql.py
@@ -153,3 +153,5 @@ DATA_TYPES = {
     'URLField':          'varchar(200)',
     'USStateField':      'varchar(2)',
 }
+
+DATA_TYPES_REVERSE = {}