Consider a checkpoint protocol and the following operations in the log.Question One

[start_transaction,T4]

[Write_Item,T4,D,20,30]

[start_transaction,T1]

[Commit, T4]

[Write_Item,T1,C,5,9]

[Checkpoint]

[start_transaction,T2]

[Write_Item,T2,B,3,9]

[Commit, T2]

[start_transaction,T3]

[Write_Item,T3,C,9,15]

..CRASH.

when a crash happens, the recovery system tries to recover by using both undo and redo operations. what are the transaction(s) of the undo list and the redo list?

UNDO	REDO

5 Marks

Question Two

A) List the main control measures that are used to provide security of data in databases?

B) Explain briefly about Access Protection, User Accounts, and Database Audits

3 Marks

Question three

What are the main potential advantages of distributed database?

5 Marks

Question Four

What are triggers? How to invoke a trigger on demand? List the four instances when triggers are appropriate?

8 Marks

Question Five

Consider the project relation :

project

PNo	Pname	Budget	Location
p1	Database develop	250,000	riyadh
p2	Maintenance	125,000	jeddah
p3	CAD	170,000	abha
p4	Design	200,000	madinah
p5	instrumentation	100,000	qasim

apply horizontal fragmentations:

table1 projects with budget less than 150,000.

b. table2 projects with budget greater than or equal to 150,000.

2. apply vertical fragmentations :

table1 information about project budget.

table2 information about projects names and locations.