diff --git a/htdocs/install/mysql/tables/llx_facturedet.sql b/htdocs/install/mysql/tables/llx_facturedet.sql
index afd9a420c89..73e64fa1c6a 100644
--- a/htdocs/install/mysql/tables/llx_facturedet.sql
+++ b/htdocs/install/mysql/tables/llx_facturedet.sql
@@ -75,12 +75,6 @@ create table llx_facturedet
   multicurrency_total_ht		double(24,8) DEFAULT 0,
   multicurrency_total_tva		double(24,8) DEFAULT 0,
   multicurrency_total_ttc		double(24,8) DEFAULT 0,
-  ref_ext varchar(255)
+  ref_ext varchar(255) DEFAULT NULL
 )ENGINE=innodb;
 
--- 
--- List of codes for special_code
---
--- 1 : frais de port
--- 2 : ecotaxe
---