diff --git a/html/admin/sql/patch/upgrade5.sql b/html/admin/sql/patch/upgrade5.sql
index 1b89eef3f..f0240c0cf 100644
--- a/html/admin/sql/patch/upgrade5.sql
+++ b/html/admin/sql/patch/upgrade5.sql
@@ -94,3 +94,6 @@ insert into parameter (pr_id) values ('MY_NUMBER');
 
 
 update  version set val=6;
+
+--make sure that p_start < p_end 
+ALTER TABLE parm_periode ADD CHECK (p_end >= p_start);