diff --git a/mysql/migration/2.0.0-2.1.0.sql b/mysql/migration/2.0.0-2.1.0.sql
index 5c1f5f748d9..8962413f000 100644
--- a/mysql/migration/2.0.0-2.1.0.sql
+++ b/mysql/migration/2.0.0-2.1.0.sql
@@ -88,7 +88,7 @@ create table llx_comfourn_facfourn
 
 alter table llx_categorie drop column fk_statut;
 alter table llx_categorie add visible tinyint DEFAULT 1 NOT NULL;
-
+ALTER TABLE llx_categorie ADD UNIQUE INDEX uk_categorie_ref (label);
 
 alter table llx_c_actioncomm  add module varchar(16) DEFAULT NULL after libelle;
 
diff --git a/mysql/tables/llx_categorie.key.sql b/mysql/tables/llx_categorie.key.sql
new file mode 100644
index 00000000000..9c2617ab70d
--- /dev/null
+++ b/mysql/tables/llx_categorie.key.sql
@@ -0,0 +1,20 @@
+-- ============================================================================
+-- Copyright (C) 2007 Laurent Destailleur  <eldy@users.sourceforge.net>
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; either version 2 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program; if not, write to the Free Software
+-- Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+--
+-- ============================================================================
+
+ALTER TABLE llx_categorie ADD UNIQUE INDEX uk_categorie_ref (label);