diff --git a/include/constant.php b/include/constant.php
index 4353f3926..73d32fdd3 100644
--- a/include/constant.php
+++ b/include/constant.php
@@ -116,7 +116,7 @@ if (!defined("NOALYSS_PACKAGE_REPOSITORY")) {
 if (!defined("SYSINFO_DISPLAY")) {
     define("SYSINFO_DISPLAY", TRUE);
 }
-define("DBVERSION", 180);
+define("DBVERSION", 181);
 define("MONO_DATABASE", 25);
 define("DBVERSIONREPO", 20);
 define('NOTFOUND', '--not found--');
diff --git a/include/sql/patch/upgrade181.sql b/include/sql/patch/upgrade181.sql
new file mode 100644
index 000000000..137335a52
--- /dev/null
+++ b/include/sql/patch/upgrade181.sql
@@ -0,0 +1,11 @@
+begin;
+
+
+-- create constraint
+alter table operation_tag add constraint tag_operation_uq unique (jrn_id,tag_id);
+
+-- remove duplicate
+delete from operation_tag where opt_id in (select a.opt_id from operation_tag a join operation_tag b on (a.jrn_id=b.jrn_id and a.tag_id=b.tag_id) where a.opt_id  < b.opt_id );
+
+insert into version (val,v_description) values (182,'Prevent to add several time same tag on an operation');
+commit;
\ No newline at end of file