Classical

Database MCQ - Database design

16:  

The relation scheme student performance (name, courseNo, rollNo, grade) has the following functional dependencies:
name, curseNo --> grade
Rol INo, courseNo —> grade
name —> rollNo
rollNo —> name
The highest normal form ofthis relation scheme is:

A.

2 NF

B.

3 NF

C.

BCNF

D.

4 NF

 
 

Option: B

Explanation :


17:  

 Which-one ofthe following statements about normal forms is FALSE?

A.

BCNF is stricter than 3 NF

B.

Lossless, dependency -preserving decomposition into 3 NF is always possible

C.

Loss less, dependency - preserving decomposition into BCNF is always possible

D.

Any relation with two attributes is BCNF

 
 

Option: C

Explanation :


18:  

Consider a relation scheme R = (A, B, C, D, E, H) on which the following functional dependencies hold: {A —> B, BC ---> D, E, —> C, D —> Al . What are the candidate keys of R?

A.

AE, BE

B.

AE, BE, DE

C.

AEH, BEH, BCH

D.

AEH, BEH, DEH

 
 

Option: D

Explanation :


19:  

The following functional dependcies are given:
AB -> CD, AF —> D, DE --> F, C —> G, F —› E, G --> A
Which one of the following options is false?

A.

{CF}+ = {ACDEFG}

B.

{BG}± = {ABCDG}

C.

{AE }+ = {ACDEFG}

D.

{AC = {ACDFG}

 
 

Option: C

Explanation :


20:  

 Which one ofthe following statements is FALSE?

A.

Any relation with two attributes is in BCNF

B.

A relation in which every key has only one attributes is in 2NF

C.

A prime attribute can be transitively dependent on a key in 3 NF relation

D.

A prime attribute can be transitively dependent on a key in a BCNF relation

 
 

Option: D

Explanation :




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