UGC NET · PAPER 2
UGC NET Paper 2 Computer Science – Unit 4: Database Management Systems PYQ (22 June 2026)
Q74. 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?
- M
- {M, Y}
- {M, C}
- MP
Q91. Which of the following relational algebraic expressions is equivalent to the SQL query SELECT X FROM B WHERE Y ?
- σy(πx(B))
- πy(σx(B))
- σx(πx(B))
- πx(σy(B))
Q93. A safe expression in relational calculus is one that is guaranteed to yield
- Finite number of tuples
- Finite number of attributes
- Finite number of null values
- Finite number of indices
Q121. In order to define the relationship between two entity sets, which of the following operations can be used?
- Concatenation
- Adding
- Cartesian product
- Union
Q135. 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 primary key.
Choose the correct answer from the options given below:
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 primary key.
Choose the correct answer from the options given below:
- A, C, D only
- A, D, E only
- B, C, D only
- B, D, E only
Q138. 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 below:
A. Create conceptual schema
B. Data model mapping
C. Requirements collection and analysis
D. Physical design
Choose the correct answer from the options given below:
- C, A, B, D
- C, B, A, D
- A, B, C, D
- A, C, B, D
Q140. Match the LIST-I with LIST-II
Choose the correct answer from the options given below:
| LIST-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. Used to check serializability |
- A-III, B-IV, C-I, D-II
- A-III, B-IV, C-II, D-I
- A-IV, B-I, C-II, D-III
- A-IV, B-III, C-II, D-I