Database Management System Set 21

Database Management System

201.

The file organization which allows us to read records that would satisfy the join condition by using one block read is

(a)	Heap file organization
(b)	Sequential file organization
(c)	Clustering file organization
(d)	Hash file organization
(e)	Index file organization.

202.

Which of the following is true with respect to the B+ tree index method?

(a)	Records are physically stored in primary key order
(b)	B+ trees use a hashing algorithm
(c)	The index tree may become unbalanced as a result of updates
(d)	Only the primary key field may have a B+ tree index
(e)	Records are physically stored in secondary key order.

203.

Which of the following lock prevents the use of any tables in the database from one transaction while another transaction is being processed?

204.

Which of the following is not an ACID property?

205.

What is the result of the following query? SELECT FLOOR(3.6) FROM DUAL?

206.

Which of the following statement(s) is/are true for two-phase locking?

I. Lock acquisition is the second phase

II. Locks can be acquired at any time

III. Keys are acquired in the first phase

IV. Locks can only be acquired on primary keys

207.

The means that data used during the execution of a transaction cannot be used by a second transaction until the first one is completed is called

208.

What is the extent of the database resource that is included with each lock called?

209.

Which of the following facility is used by DBMS that periodically suspends all processing and synchronizes its files and journals?

210.

Which of the following is not true about B+ trees?

(a)	B+ tree index takes the form of balanced tree
(b)	Performance of B+ tree degrades as the file grows
(c)	Look-up in B+ tree is straightforward and efficient
(d)	Insertion and deletion in B+ tree is complicated but efficient
(e)	Insertion and deletion in B+ tree is simple but complex.

201.	Answer : (c) Reason : Clustering file organization allows us to read records that would satisfy the join condition by using one block read.
202.	Answer : (a) Reason : B+ tree the records are stored in primary key order.
203.	Answer : (a) Reason : Data base-level lock prevents the use of any tables in the database from one transaction while other transaction is being processed.
204.	Answer : (b) Reason : concurrency is not considered as an ACID property.
205.	Answer : (b) Reason : The floor function rounds of to the nearest value.
206.	Answer : (e) Reason : Locks can be acquired at any time and their acquisition is the second phase, keys are aquired in the first phase, locks can only be acquired on primary keys.
207.	Answer : (c) Reason : Isolation means that data used during the execution of a transaction can’t be used by a second transaction until the first one is completed.
208.	Answer : (b) Reason : The extent of the database resource that is included with each lock is called the level of Granularity.
209.	Answer : (a) Reason : DBMS periodically suspends all processing and synchronizes its files and journals through the use of Check point facility.
210.	Answer : (b) Reason : Performance of B+ tree degrades as the file grows.