A functional view of multilevel databases

I n a multilevel secure database management system @US/DBMS) users cleared at different security levels access and share a database consisting of data at various sensitivity levels. Recently, many attempts have been made to design ML’S/ DBMSs [5-7, 131. Most of these designs concentrate on the relational data model [4]. Although the relational model has strong theoretical foundations, it does have some limitations. They include the following.