diff --git a/database/db_types.anubis b/database/db_types.anubis
index 7af3b98..30a842e 100644
--- a/database/db_types.anubis
+++ b/database/db_types.anubis
@@ -319,6 +319,13 @@ public define String
   to_String(dt) + s
 .
 
+public define Bool 
+  DB_datetime a < DB_datetime b
+  =
+  //convert datetime in String to allows String comparison
+  a.datetime < b.datetime
+.
+
 public define String
   get_time
   (
--
libgit2 0.21.4