diff --git a/mysql/tables/llx_facture_fourn.sql b/mysql/tables/llx_facture_fourn.sql
index f24acd7f7ed..4ad890a4cf6 100644
--- a/mysql/tables/llx_facture_fourn.sql
+++ b/mysql/tables/llx_facture_fourn.sql
@@ -44,5 +44,5 @@ create table llx_facture_fourn
 
   note       text,
 
-  UNIQUE INDEX (facnumber)
+  UNIQUE INDEX (facnumber, fk_soc)
 );