topic - solutions adda

Candidate-key

Please wait while the activity loads.
If this activity does not load, try refreshing your browser. Also, this page requires javascript. Please visit using a browser with javascript enabled.

If loading fails, click here to try again

Question 1

Given the STUDENTS relation as shown below.

For (StudentName, StudentAge) to be the key for this instance, the value X should not be equal to

A	19
B	20
C	21
D	22

Database-Management-SystemCandidate-keyGATE 2014 [Set-2]Video-Explanation

Question 1 Explanation:

There is already one entry with StudentName as “Shankar” and Age as 19. So, X value should not be 19.

Question 2

The maximum number of superkeys for the relation schema R(E, F, G, H) with E as the key is _____.

A	8
B	9
C	10
D	11

Database-Management-SystemCandidate-keyGATE 2014 [Set-2]Video-Explanation

Question 2 Explanation:

Maximum no. of possible super keys for a relation with n attributes with one candidate key (only one attribute) = 2^n-1
Here, n = 4.
So, the possible super keys = 2^4-1 = 8
The super keys are: E, EH, EG, EF, EGH, EFH, EFG, EFGH.

There are 2 questions to complete.

Access quiz wise question and answers by becoming as a solutions adda PRO SUBSCRIBER with Ad-Free content

If you have registered and made your payment please contact solutionsadda.in@gmail.com to get access