UGC NET · PAPER 2
UGC NET Paper 2 Computer Science – Unit 4: Database Management Systems PYQ (June 2024 Re-Exam)
Q2. 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:
- In 1NF, but not in 2NF
- In 2NF, but not in 3NF
- In 3NF, but not in BCNF
- In BCNF
Q8. Consider a relation schema R = (U, V, W, X, Y, Z), on which the following functional dependencies hold: {U → V, VW → X, Y → W, X → U}. The candidate keys of R are:
- UY, VY
- UY, VY, XY
- UYZ, VYZ, VWZ
- UYZ, VYZ, XYZ
Q21. 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:
- Dependency preserving and lossless join
- Lossless join but not dependency preserving
- Dependency preserving but not lossless join
- Not dependency preserving and not lossless join
Q28. What is SQL primarily used for in the context of relational databases?
- To design user interfaces
- To create and manipulate databases
- To display data on web pages
- To format printed reports
Q31. How does a relational database ensure data integrity?
- By encrypting all data stored
- By enforcing rules defined in the schema
- By compressing data for efficient storage
- By allowing unrestricted access to all users
Q35. Fifth normal form is concerned with:
- Join Dependency
- Domain-Key
- Multivalued dependency
- Functional dependency
Q36. Consider the transactions T1, T2, T3 and the schedules S1 and S2 given below.
T1: r1(x); r1(z); w1(z)
T2: r2(y); r2(z); w2(z)
T3: r3(y); r3(x); w3(y)
S1: r1(x); r3(y); r3(x); r2(y); r2(z); w3(y); w2(z); r1(z); w1(x); w1(z)
S2: r1(x); r3(y); r2(y); r3(x); r1(z); r2(z); w3(y); w1(x); w2(z); w1(z)
Which one of the following statements about the schedules is TRUE?
T1: r1(x); r1(z); w1(z)
T2: r2(y); r2(z); w2(z)
T3: r3(y); r3(x); w3(y)
S1: r1(x); r3(y); r3(x); r2(y); r2(z); w3(y); w2(z); r1(z); w1(x); w1(z)
S2: r1(x); r3(y); r2(y); r3(x); r1(z); r2(z); w3(y); w1(x); w2(z); w1(z)
Which one of the following statements about the schedules is TRUE?
- Only S1 is conflict-serializable
- Only S2 is conflict-serializable
- Both S1 and S2 are conflict-serializable
- Neither S1 nor S2 is conflict-serializable
Q41. Which of the following relations can NOT be decomposed into BCNF with a lossless join and dependency-preserving decomposition?
- R(V, W, X, Y, Z) {VW → X, WX → V, VX → W, W → Y, Y → Z}
- R(V, W, X, Y, Z) {VW → W, X → Y}
- R(V, W, X, Y, Z) {VW → X, X → VY}
- R(V, W, X, Y, Z) {VW → X, X → Y, Y → Z, Z → V}
Q44. Which of the following best describes the structure of a relational database?
- Data organized into tables with rows and columns
- Data organized into files and folders
- Data organized into a hierarchical tree structure
- Data organized into a network of interconnected nodes
Q67. 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) Physical Design
(B) Conceptual Design
(C) Logical Design
(D) Requirement Analysis
Choose the correct answer from the options given below:
- (B), (D), (A), (C)
- (C), (A), (B), (D)
- (D), (B), (C), (A)
- (A), (D), (C), (B)