diff --git a/htdocs/install/mysql/tables/llx_element_categorie.key.sql b/htdocs/install/mysql/tables/llx_element_categorie.key.sql
new file mode 100644
index 00000000000..0367eddc0a1
--- /dev/null
+++ b/htdocs/install/mysql/tables/llx_element_categorie.key.sql
@@ -0,0 +1,22 @@
+-- ============================================================================
+-- Copyright (C) 2022 Charlene Benke <charlene@patas-monkey.com>
+--
+-- 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 3 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, see <https://www.gnu.org/licenses/>.
+--
+-- ============================================================================
+
+
+ALTER TABLE llx_element_categorie ADD UNIQUE INDEX idx_element_categorie_idx1 (fk_element, fk_categorie);
+	
+ALTER TABLE llx_element_contact ADD CONSTRAINT fk_element_categorie_fk_categorie FOREIGN KEY (fk_categorie)     REFERENCES llx_fk_categorie(rowid);