Question $4$

$($a$)$ Explain the importance of parallel query processing in a parallel

Database. Discuss, with suitable examples, how parallelism can be

achieved in query execution. $(8)$

$($b$)$ The simple security property and the star property are two constraints

in the Bell$-$Lapadula model. Explain these properties. $(8)$

$($c$)$ Explain the term deductive databases. Show how the relational

operators select, project and join can be expressed in a deductive

database