diff --git a/mod/quiz/db/upgrade.php b/mod/quiz/db/upgrade.php
index 4cff3d89d1c..07b41df5065 100644
--- a/mod/quiz/db/upgrade.php
+++ b/mod/quiz/db/upgrade.php
@@ -19,7 +19,7 @@
 
 function xmldb_quiz_upgrade($oldversion=0) {
 
-    global $CFG, $THEME;
+    global $CFG, $THEME, $db;
 
     $result = true;