One of the most important elements of the database security is properly maintaining user accounts, i.e. database users, their passwords, profiles, etc.
ABSTRACT
Distributed database systems come with new kinds of security problems. If the number of users is more than a few, then it is not easy to manage user accounts even in centralized database, especially in distributed database.
With multiple numbers of databases in distributed database system, it often happens that the users must have accounts in two or more databases (some even in all databases).
One of the ways to manage user accounts in distributed database is to manage it on every database separately. In some cases that solution can be satisfying. However, a large number of users, even when the number of databases is relatively small, have become a problem for security manager.
A large number of passwords for each user (different for each database), can decrease security since the users either use simple passwords, easy to remember, or write them down if they are complicated. That is why central maintenance of user accounts is the most convenient way to manage distributed database systems. In some cases we can use more sophisticated and more expensive (Oracle) solutions, and sometimes we have to resort to our own solutions, which can be less sophisticated, but cheaper.