Question:

(a) In the context of database security explain how the following database features help to enforce security in the database system:

(i) Authorisation
(ii) Access Control
(iii) Views

(b) Database security involves measures to avoid loss of privacy and loss of confidentiality. Explain what is meant by the above terms.

(c) Write SQL code to create a view of name Toronto_finance_view that contains the employee last name, the department name and the city of all employees that works in the Finance department located in the city of Toronto.

(d) Write SQL code to give the select privilege to the view created above to Mark and Spencer.

A Deductive Database System can be conceived as a database capable of deducing additional new data from data that is explicitly represented (facts), by applying specified rules of inference to those facts (e) Discuss the main features of a deductive database system, and contrast it with a relational database system. Your discussion should include identifying the role of logic programming in a deductive database.

(f) In the context of deductive databases, explain the following concepts:

• Extensional database
• Intentional database 
• Recursive query