Paper 2 CS · UNIT 04 · MOCK TEST

Mock 6 – Functional Dependencies & Normalisation (Part 1)

Unit 4: Database Management Systems · 16 questions · about 19 minutes. Press End Mock any time to see your score and the correct answers.

All 11 topic-wise mocks in this unit

0 / 16 answered 00:00

Q1. For the relation schema r(M, Y, P, MP, C) and set of functional dependencies F = {M → MP, {M, Y} → P, MP → C}, which of the following is the key?

AM B{M, Y} C{M, C} DMP

Q2. Consider the relation T1(A, B, C, D, E) with the dependencies {EB → C, D → E, EA → B} and T2(A, B, C, D) with the dependencies {C → A, A → B, A → D}. Which of the following is TRUE?

AT1 is in 3NF BT2 is in 3NF CT1 is not in 3NF DT1 is in 2NF

Q3. In a relational database, which one of the following is CORRECT?

AA relation with only two attributes is always in BCNF. BIf all attributes of a relation are prime attributes then the relation is in BCNF. CEvery relation has at least one non-prime attribute. DBCNF decomposition preserves functional dependencies.

Q4. Which of the following is/are FALSE statement(s)?
A. An all-key relation is always in BCNF since it has no FDs.
B. A relation that is not in 4NF due to a nontrivial MVD must be decomposed to convert it into a set of relations in 4NF.
C. The decomposition removes the redundancy caused by the MVD.
D. 3NF is stronger than BCNF.
Choose the correct answer from the options given below:

AA only BA, B only CD only DC only

Q5. In a schema R(A, B, C, D, E, F, G, H), each field of R contains only atomic values. F = {CH → G, A → BC, B → CFH, E → A, F → EG} is a set of functional dependencies, and F⁺ is exactly the set of FDs that hold on R. The relation R is:

AIn 1NF, but not in 2NF BIn 2NF, but not in 3NF CIn 3NF, but not in BCNF DIn BCNF

Q6. Consider a schema R(P, Q, R, S) and the functional dependencies P → Q, Q → R, R → S, S → Q. Then the decomposition of R into R₁(P, Q), R₂(Q, R) and R₃(Q, S) is:

ADependency preserving and lossless join BLossless join but not dependency preserving CDependency preserving but not lossless join DNot dependency preserving and not lossless join

Q7. Fifth normal form is concerned with:

AJoin Dependency BDomain-Key CMultivalued dependency DFunctional dependency

Q8. Which of the following relations can NOT be decomposed into BCNF with a lossless join and dependency-preserving decomposition?

AR(V, W, X, Y, Z) {VW → X, WX → V, VX → W, W → Y, Y → Z} BR(V, W, X, Y, Z) {VW → W, X → Y} CR(V, W, X, Y, Z) {VW → X, X → VY} DR(V, W, X, Y, Z) {VW → X, X → Y, Y → Z, Z → V}

Q9. Arrange the following phases of database design in the correct order:
(A) Physical Design
(B) Conceptual Design
(C) Logical Design
(D) Requirement Analysis
Choose the correct answer from the options given below:

A(B), (D), (A), (C) B(C), (A), (B), (D) C(D), (B), (C), (A) D(A), (D), (C), (B)

Q10. Let R(A, B, C, D) be a relational schema with functional dependencies A → B, B → C, C → D and D → B. The decomposition of R into (A, B), (B, C), (B, D)

Agives a lossless join, and is dependency preserving Bgives a lossless join, but is not dependency preserving Cdoes not give a lossless join, but is dependency preserving Ddoes not give a lossless join and is not dependency preserving

Q11. Consider the following statements:
A. A database design is in BCNF if each member of the set of relation schemas that constitutes the design is in BCNF.
B. A BCNF schema can have a transitive dependency.
C. It is always possible to obtain a 3NF design without sacrificing a lossless join.
D. There are multivalued dependencies in 4NF.
Choose the correct answer from the options given below:

AA, B and C only BB, C and D only CA, B and D only DA, C and D only

Q12. Let R(A, B, C, D, E, F) be a relational schema with the functional dependencies C → F, E → A, EC → D, A → B. Which of the following is a key for R?

ACD BEC CAE DAC

Directions (Q96–100): A company is implementing a new database system to manage its customer information. The database contains tables for customers, orders, products and sales representatives. Each customer can place multiple orders and each order can contain multiple products. Each order is associated with a specific sales representative who manages the account. The database is designed to improve efficiency in tracking sales and customer interactions.

Q13. Which of the following best describes the relationship between the 'orders' table and the 'customers' table?

AOne-to-One BOne-to-Many CMany-to-One DMany-to-Many

Q14. Consider Student(stuid, dept, clsroll) with FD1: stuid → dept, FD2: dept → stuid, FD3: stuid → clsroll, FD4: clsroll → stuid, FD5: dept → clsroll. Which functional dependencies can be removed to obtain a canonical cover?
A. FD2 and FD3
B. FD1 and FD5
C. FD5
D. FD1
Choose the correct answer from the options given below:

AA, B only BA, C only CB, C only DA, B, C only

Q15. Let R(ABCDEFGH) be a relation schema and F = {A → B, ABCD → E, EF → G, EF → H, ACDF → EG} the set of dependencies. The minimal cover of F is

AA → B, ACD → E, EF → G, EF → H BA → B, ACD → E, EF → G, EF → H, ACDF → G CA → B, ACD → E, EF → G, EF → H, ACDF → E DA → B, ABCD → E, EF → H, EF → G

Q16. Match List I with List II.
Choose the correct answer from the options given below:

List I	List II
A. BCNF	I. It removes multivalued dependency.
B. 3NF	II. It is not always dependency preserving.
C. 2NF	III. It removes transitive dependency.
D. 4NF	IV. It removes partial functional dependency.

AA-III, B-II, C-IV, D-I BA-II, B-IV, C-I, D-III CA-II, B-III, C-IV, D-I DA-II, B-I, C-IV, D-III

Next: Mock 7 – Functional Dependencies & Normalisation (Part 2) →