Since databases are the primary repositories of information for today's organizations and governments, database security has become critically important. Most database security models focus on protecting against external unauthorized users. Because multilevel secure databases provide internal security according to user access type, they are a viable option for the security needs of modern database systems. Covering key concepts in database security, this book illustrates the implementation of multilevel security for relational database models. It considers concurrency control in multilevel database security and presents encryption algorithms. It also includes simulation programs and Visual studio and Microsoft SQL Server code for the simulations covered in the text.