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OTI365 - Computer Instructors Grade I-2019 Tamil Nadu
Computer Instructors Grade I - Relational Database Management System Study Materials with Answer

Computer Science - Relational Database Management System

Exam Duration: 45 Mins Total Questions : 30

1 )

The users who maintain personal databases by using readymade program packages that provide easy-to-use menu or graphics based interface, known as

(a)
Casual end user
(b)
Native end user
(c)
Sophisticated end user
(d)
Stand alone user

2 )

Given, relations R(W,Y) and S(Y,Z) the result of Select distinct W,X
From R,S is guaranteed to be same as E, if

(a)
R has no duplicates and S is non-empty
(b)
R and S have no duplicates
(c)
S has no duplicates and R is non-empty
(d)
R and S have the same number of tuples

3 )

Generally speaking, for a weak entity set to be meaningful, it be part of a

(a)
one to one relationship
(b)
one to many relationship
(c)
many to many relationship
(d)
none of the above

4 )

With the help of which of the following relations operation set we can perform division on relations?

(a)
\(\{ \pi ,\times ,-\} \)
(b)
\(\{ \sigma ,\times ,-\} \)
(c)
\(\{ \times ,-\} \)
(d)
{X}

5 )

Consider the following relation scheme pertaining to the information about a student maintained by an university:
STDINF (Name, Course, Phone no.Major, Prof, Ggrade) then this scheme is decomposed into the relation schemes
STUDENT (Name, Phone no., Major, Grade)
Course (Course, prof)
Then select correct statement if, it is a bad decomposition

(a)
due to loss of information
(b)
due to redundancy and update anomaly
(c)
The above decomposition is not at all bad
(d)
Both a and b

6 )

Consider the relation R (A, B, C, D, E, F, G) satisfies the following functional dependencies
\(A\rightarrow B,BC\rightarrow DE,AEF\rightarrow G\) Which of the following statements is true?

(a)
BC\(\rightarrow \)DC
(b)
ACF\(\rightarrow \)DG
(c)
A\(\rightarrow \)DG
(d)
B\(\rightarrow \)DG

7 )

Consider the following log sequence of two transaction on a back account, with initial balance 12000, that transfer 2000 to a mortage payment and, then apply a 5% interest.
1. T1 start
2. T1 B old = 12000 new = 10000
3. T1 M old = 0 new = 2000
4. T1 commit
5. T2 start
6. T2 B old = 10000 new = 10500
7. T2 commit
Suppose the database system crashed just before log record 7 is written.When the system is restarted,which one statement is true of the recovery procedure?

(a)
We must redo log record 6 set B to 10500
(b)
We must undo log record 6 to set B to 100000 and then redo log records 2 and 3
(c)
We need not redo log records 2 and 3 because transaction T₁ has committed
(d)
We can apply redo and undo operations in arbitary order because they are idempotent

8 )

Give the following relation instane

X	Y	Z
1	4	2
1	5	3
1	6	3
3	2	2

Which of the following functional dependencies are satisfied by the instance?

(a)
XY -> Z and Z -> Y
(b)
YZ -> X and Y -> Z
(c)
YZ -> X and X -> Z
(d)
XZ -> Y and Y -> X

9 )

In the index allocation scheme of vblocks to a file,the maximum possible size of the file depends on

(a)
the size of the blocks, and the size of the address of the blocks
(b)
the number of blocks used for the index and the size of the blocks
(c)
the size of the blocks, the number of blocks used for the index and the size of the address of the blocks
(d)
None of the above

10 )

Consider a schema R (A,B,C,D) and functional dependencies A\(\rightarrow \)B and C\(\rightarrow \)D. Then the decomposition of R into R₁ (AB) and R₂ (CD) is

(a)
dependency preserving and lossless join
(b)
lossless join but not dependency preserving
(c)
dependency preserving but not lossless join
(d)
not dependence preserving and not lossless join

11 )

Cascading rollback can be avoided by

(a)
two phase locking protocol
(b)
strict two phase locking protocol
(c)
cannot be avoided
(d)
can be avoided but there is no actual protocol

12 )

In lock conversion what is true?

(a)
Upgrade can be done in growing phase and downgrading in shrinking phase
(b)
Upgrade can be done in shrinking phase and downgrading in growing phase
(c)
Upgrade and downgrade cannot be possible
(d)
Lock conversion can be allowed arbitraily

13 )

In vigorous two phase locking protocol a transaction

(a)
release exclusive locks only at the end of transaction
(b)
release all locks only at the beginning of transaction
(c)
acquired all locks at the beginning of transaction
(d)
acquired all exclusive locks at the beginning of transaction

14 )

In B tree file organization, the highest number of itm can be placed in leaf nodes is

(a)
n/2
(b)
(n-1)/2
(c)
n-1
(d)
n

15 )

In dense index, index record contains

(a)
a search key value and a pointer to the first record
(b)
longest search key value and a pointer to last record
(c)
smallest search key value and a pointer to the first location
(d)
None of the above

16 )

Commonly a database consists of a ....... process that provides data from secondary storage to one or more ........ process that are application using the data.