Database Management Systems – Previous Year Questions
218 questions from past UGC NET Paper 2 – Computer Science papers, each with the correct answer. Open any question for its explanation.
- 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?
- Which of the following relational algebraic expressions is equivalent to the SQL query SELECT X FROM B WHERE Y ?
- A safe expression in relational calculus is one that is guaranteed to yield
- In order to define the relationship between two entity sets, which of the following operations can be used?
- Which of the following are true? A. A database may have only one primary key B. Every key is a candidate key C. There can be multiple candidate keys D. There can be more than one super keys E. Every candidate key is a p…
- What is the correct sequence of database design process? A. Create conceptual schema B. Data model mapping C. Requirements collection and analysis D. Physical design Choose the correct answer from the options given belo…
- Match the LIST-I with LIST-IILIST-I LIST-II A. Wait-for graph I. Holds all locks until it commits B. Precedence graph II. Holds write-locks until it commits C. Rigorous 2PL III. Use to check deadlocks D. Strict 2PL IV.…
- Consider the following three relations: Employee(eid, eName), Comp(cid, cName), Own(eid, cid). Which of the following relational algebra expressions returns the set of eids who own all brands?
- Consider R(A, B, C, D, E) be a relation with the following dependencies: C → F, E → A, EC → D, A → B. Which of the following is a key for R?
- Consider the following statements: A. Data transformation is involved in the Data mining process. B. Online database is used in Data warehouse. C. Classification is a measure of accuracy. D. K-means clustering algorithm…
- 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?
- In a relational database, which one of the following is CORRECT?
- Consider the following statements: A. A non-serial schedule is said to be conflict serializable if it is conflict-equivalent to some serial schedule. B. A non-serial schedule is said to be view serializable if it is vie…
- What will be the right sequence of the phases of database design? A. Physical Design B. Conceptual Design C. Logical Design D. Requirement collection and analysis Choose the correct answer from the options given below:
- An alternate key in a database table is also called
- In concurrency control, the phantom problem may occur when
- 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 rel…
- Which of the following commands can be used to modify data in an SQL table? A. INSERT B. DELETE C. UPDATE D. SELECT Choose the correct answer from the options given below:
- Which of the following tables contains the primary information in a data warehouse?
- The INSERT command is used to A. add a single tuple to a relation B. add multiple tuples to a relation C. add values to specific attributes D. insert a new table Choose the correct answer from the options given below:
- Match List I with List IIList I List II A. Hadoop Distributed File System I. Trust B. Veracity II. Facebook C. Apache Pig III. Name-Node D. Apache Hive IV. Yahoo
- The degree of a relation in a database is
- Match List I with List IIList I List II A. Project Join Normal Form I. Concurrency B. The lost update problem II. Fifth Normal Form C. Discretionary Access Control III. SQL D. Data Manipulation Language IV. Security
- 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…
- 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:
- 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:
- What is SQL primarily used for in the context of relational databases?
- How does a relational database ensure data integrity?
- Fifth normal form is concerned with:
- 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…