diff --git a/app/controllers/api/databases.php b/app/controllers/api/databases.php
index 4e82cad0dc..c0a8abd60c 100644
--- a/app/controllers/api/databases.php
+++ b/app/controllers/api/databases.php
@@ -102,7 +102,7 @@ function createAttribute(string $databaseId, string $collectionId, Document $att
 
     if ($type === Database::VAR_RELATIONSHIP) {
         $options['side'] = Database::RELATION_SIDE_PARENT;
-        $relatedCollection = $dbForProject->getDocument('database_' . $db->getInternalId(), $options['relatedCollection']);
+        $relatedCollection = $dbForProject->getDocument('database_' . $db->getInternalId(), $options['relatedCollection'] ?? '');
         if ($relatedCollection->isEmpty()) {
             throw new Exception(Exception::COLLECTION_NOT_FOUND);
         }