diff --git a/create_user_table.sql b/create_user_table.sql
index 51b916a..ae935dc 100644
--- a/create_user_table.sql
+++ b/create_user_table.sql
@@ -24,6 +24,7 @@
     total_due decimal(10,2) not null default 0.00,
     registered_at timestamp default '0000-00-00 00:00:00', 
     updated_at timestamp default now() on update now(),
-    invoice BLOB,
+    invoice MEDIUMBLOB,
+    invoice_reference varchar(32) not null default '',
   primary key (`id`)
 ) engine=innodb AUTO_INCREMENT=100;