Flexibility is important for customer, because our purpose is to create a platform for learning to work with databases. But there are can be countless amount of types of databases. So flexibility will allow users to freely study any database they want.
Security is importan for customer, since with a sufficient level of security one user can’t change or delete database of other users. Moreover, security will not allow to users change the database of the platform itself.
Reliability is important for customer, since the platform is design for university students. It means that a lot of people will be at the platform at the same time.