diff --git a/grammars/database/DatabaseI.gf b/grammars/database/DatabaseI.gf
index 204e43c81..13694416b 100644
--- a/grammars/database/DatabaseI.gf
+++ b/grammars/database/DatabaseI.gf
@@ -1,6 +1,6 @@
 --# -path=.:../newresource/abstract:../prelude
 
-incomplete concrete DatabaseI of Database = open Prelude, Resource in {
+incomplete concrete DatabaseI of Database = open Prelude, Resource, Structural in {
 
 flags lexer=text ; unlexer=text ;