diff --git a/htdocs/install/mysql/migration/6.0.0-7.0.0.sql b/htdocs/install/mysql/migration/6.0.0-7.0.0.sql
index df1b40dffd8..6749d4be51c 100644
--- a/htdocs/install/mysql/migration/6.0.0-7.0.0.sql
+++ b/htdocs/install/mysql/migration/6.0.0-7.0.0.sql
@@ -99,6 +99,8 @@ insert into llx_c_action_trigger (code,label,description,elementtype,rang) value
 insert into llx_c_action_trigger (code,label,description,elementtype,rang) values ('MEMBER_SUBSCRIPTION_MODIFY','Member subscribtion modified','Executed when a member subscribtion is modified','member',24);
 insert into llx_c_action_trigger (code,label,description,elementtype,rang) values ('MEMBER_SUBSCRIPTION_DELETE','Member subscribtion deleted','Executed when a member subscribtion is deleted','member',24);
 
+-- VPGSQL8.4 ALTER TABLE llx_product_attribute DROP CONSTRAINT unique_ref;
+
 ALTER TABLE llx_product_attribute_value DROP INDEX unique_ref;
 ALTER TABLE llx_product_attribute_value ADD UNIQUE INDEX uk_product_attribute_value (fk_product_attribute, ref);