alter table notificationrole_notification add column isread varchar(3) not null default 'no';
ALTER TABLE notificationrole_notification ADD CONSTRAINT notificationrole_notification_isread_check CHECK (isread IN ('yes', 'no'));
CREATE UNIQUE INDEX notificationrole_notification_notificationrole_notification_roleindex_index ON
       notificationrole_notification(notificationrole, notification, roleindex);
