Add SecuredAttribute table Foreign Key FROM external_sys_attr.external_sys_id TO external_sys.id Add SystemSecuredValue table Foreign Key FROM external_sys_attr_sys_val.external_sys_attr_id TO external_sys_attr.id Create an index for the FK external_sys_attr_sys_val.external_sys_attr_id Add UserSecuredValue table Foreign Key FROM external_sys_attr_usr_val.external_sys_attr_id TO external_sys_attr.id Foreign Key FROM external_sys_attr_usr_val.usr_id TO usr.id Create an index for the FK external_sys_attr_usr_val.external_sys_attr_id