Normalize the table, find keys, find minimal cover - Solved exercise

Normalization Quiz - Find the keys, candidate keys of a relational table, find the minimal cover of set of functional dependencies, check whether two sets of FDs are equivalent


Normalization – Find keys, find minimal cover, check for equivalent FDs

 

1. Let F = {A B, AB E, BG E, CD I, E C}. The closures, A+, (AE)+ and (ADE)+ will be ________.
(a) ABCE, ABDE, ABCDEI
(b) ABCE, ABCE, ABCDEI
(c) ABDE, ABCE, ABCDE
(d) ABCE, ABDE, ABCDI


2. Let F = {A B, A C, BC D}. Can A determine D uniquely?
(a) Yes
(b) No

3. Let F = {AB D, B C, BC D}. Can AC determine D uniquely?
(a) Yes
(b) No

4. Let F1 = {A C, AC D, E AD} and F2 = {A CD, E AH}. Are F1 and F2 are equivalent?
(a) Equivalent
(b) Not Equivalent

5. Find the minimal cover of the set of functional dependencies given; {A BC, B C, AB D}
(a) {A C, B C, AB D}
(b) {A C, B C, B D}
(c) {A B, B C, A D}
(d) {A BC, B C, A D}


6. Find the minimal cover of the set of functional dependencies given; {A C, AB C, C DI, CD I, EC AB, EI C}
(a) {A C, C DI, C I, E A, EI C}
(b) {A C, C D, C I, EC A, EI C}
(c) {B C, C DI, D I, E AB, EI C}
(d) {A C, C DI, CD I, I C}


7. Consider a relation R with set of functional dependencies F as follows; {A B, C D, AC E, D F}. How many keys does R have and what are they?
(a) 1, {(AC)}
(b) 2, {(AC), (AD)}
(c) 3, {(AC), (BC), (ABD)}
(d) 2, {(AC), (ABD)}


8. Consider a relation R(A, B, C, D, E) with FDs AB C, CD E, C A, C D, D B. What are the keys of R?
(a) AB, AC, D
(b) AC, BD
(c) AC, AD
(d) AB, AD, C
Solution: Visit for detailed answer here.


9. Consider a relation R(A, B, C, D, E) with FDs AB C, C A, C BD, D E. What are the keys of R? Decompose R into 3NF relations.
(a) {C}, R1(ABCD), R2(DE)
(b) {BD, AB}, R1(ABCD), R2(DE)
(c) {AB, C}, R1(ABCD), R2(DE)
(d) {BD}, R1(ABC), R2(CDE)
Solution: Visit for detailed answer here.


10. Consider a relation with schema R(A, B, C, D) with functional dependencies, BC A, AD B, CD B, AC D. Find all the candidate keys of R.
(a) AC, BC, CD
(b) AC, BC
(c) AC, AD
(d) BC, CD, A
Solution: Visit for detailed answer here.


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