diff --git a/core/modules/node/node.install b/core/modules/node/node.install
index ebbce13..32bd258 100644
--- a/core/modules/node/node.install
+++ b/core/modules/node/node.install
@@ -121,6 +121,7 @@ function node_schema() {
       'uid'                 => array('uid'),
       'tnid'                => array('tnid'),
       'translate'           => array('translate'),
+      'langcode'            => array('langcode'),
     ),
     'unique keys' => array(
       'vid' => array('vid'),