Database on going is kind of works that you have an application running - with valid data and active customers that is Capital off your business and spend so many years to collect them. - But its need changes. Maybe because your business was growing, the word changed and . . . , and you need your Wealthy data to be safe and steel valid, you need the changes in application be extremity Without Errors and bugs to keep the trust of your dear customer. And in same time you need to upgrade your software architecture and make the tech update.