List five responsibilities of a database management system.

Q) List five responsibilities of a database management system. For each responsibility, explain the problems that would arise if the responsibility were not discharged.

Answer: A general purpose database manager (DBM) has five responsibilities:

a. interaction with the file manager.

b. integrity enforcement.

c. security enforcement.

d. backup and recovery.

e. concurrency control.

If these responsibilities were not met by a given DBM (and the text points out that sometimes a responsibility is omitted by design, such as concurrency control on a single-user DBM for a micro computer) the following problems can occur, respectively:

a. No DBM can do without this, if there is no file manager interaction then nothing stored in the files can be retrieved.

b. Consistency constraints may not be satisfied, account balances could go below the minimum allowed, employees could earn too much overtime (e.g., hours > 80) or, airline pilots may fly more hours than allowed by law.

c. Unauthorized users may access the database, or users authorized to access part of the database may be able to access parts of the database for which they lack authority. For example, a high school student could get access to national defense secret codes, or employees could find out what their supervisors earn.

d. Data could be lost permanently, rather than at least being available in a consistent state that existed prior to a failure.

e. Consistency constraints may be violated despite proper integrity enforcement in each transaction. For example, incorrect bank balances might be reflected due to simultaneous withdrawals and deposits, and so on.

Q) What are five main functions of a database administrator?

Answer: Five main functions of a database administrator are:

•  To create the scheme definition


•  To define the storage structure and access methods


•  To modify the scheme and/or physical organization when necessary


•  To grant authorization for data access


•  To specify integrity constraints

Q) List seven programming languages that are procedural and two that are nonprocedural. Which group is easier to learn and use? Explain your answer.

Answer: Programming language classification:

• Procedural: C, C++, Java, Basic, Fortran, Cobol, Pascal


• Non-procedural: Lisp and Prolog

Note: Lisp and Prolog support some procedural constructs, but the core of both these languages is non-procedural.

In theory, non-procedural languages are easier to learn, because they let the programmer concentrate on what needs to be done, rather than how to do it. This is not always true in practice, especially if procedural languages are learned first.

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