A$2.$

a$)$ Describe the main recovery techniques that many DBMS $($Database Management

Systems$)$ provide to safeguard and protect data as a result of EACH of the following

events:

i$)$ Human Error: an employee may unintentionally delete some data or may have used

a routine that has modified the data unknowingly in a way that would cease the

DBMS from interacting with the database effectively.

ii$)$ Network failure where a connection of a database to a shared network has been

interrupted.

iii$)$ Database software failure: this might be the result of the DBMS crashing

unexpectantly.

iv$)$ Media Failure with possible loss of all or some data.

v$)$ National catastrophe such as an earthquake or flood meaning the entire operation

of the host DBMS is lost.

$(15$ marks$)$

b$)$ Describe the security measures and precautions that a DBA $($Database Administrator$)$ must

have in place to prevent the database from being subject to hacking, for example, someone

trying to steal data.

$(5$ Marks$)$

c$)$ A data dictionary holds information that is crucial for the correct operation of a database. If

the data dictionary is lost, the database cannot operate.

Describe the contents of a typical data dictionary.

$(5$ marks$)$