UGC NET · PAPER 2
UGC NET Paper 2 Computer Science – Unit 4: Database Management Systems PYQ (December 2022 Shift 2)
Q14. Identify the incorrect statement.
- A candidate key is a minimal set of one or more attributes that, taken collectively, allows us to uniquely identify any entity in the entity set.
- A candidate key for which no proper subset is also a candidate key is called a super key.
- A super key is a set of one or more attributes that, taken collectively, allows us to uniquely identify any entity in the entity set.
- A super key for which no proper subset is also a super key is called a candidate key.
Q15. Consider the two relations below (primary keys: EMP.eid and DEPT.did). Identify all possible foreign key(s) based only on the two relations.
EMP (eid, ename, did)
DEPT (did, dname)
EMP (eid, ename, did)
DEPT (did, dname)
- eid
- did
- eid, did
- eid, did, ename
Q16. Which of the following statements is correct according to the following instance of the relational schema R(X, Y, Z)?
| X | Y | Z |
|---|---|---|
| 1 | 1 | a |
| 1 | 1 | a |
| 2 | 1 | b |
| 3 | 2 | b |
- X → Y, Z → X
- Y → Z, Z → X
- X → Y, X → Z
- Y → X, X → Z
Q48. What are the drawbacks of using file systems to store data?
1. Data inconsistency
2. Difficulty in accessing data
3. Data isolation
4. Atomicity of updates
Choose the correct answer from the options given below:
1. Data inconsistency
2. Difficulty in accessing data
3. Data isolation
4. Atomicity of updates
Choose the correct answer from the options given below:
- 1, 2 only
- 2, 3, 4 only
- 1, 2, 3 only
- 1, 2, 3, 4
Q49. In which of the following database models do we have a parent-child relationship?
1. Hierarchical databases
2. Network databases
3. Relational databases
Choose the correct answer from the options given below:
1. Hierarchical databases
2. Network databases
3. Relational databases
Choose the correct answer from the options given below:
- 1, 2
- 1, 3
- 2, 3
- 1, 2, 3
Q50. Identify the correct operation that produces the given output from the two relations R1 and R2.
R1
| Name | Class |
|---|---|
| a1 | 9 |
| b1 | 5 |
| c1 | 6 |
| d1 | 11 |
R2
| Name | Class |
|---|---|
| b1 | 5 |
| f1 | 8 |
Output
| Name | Class |
|---|---|
| b1 | 5 |
- R1 ∩ R2
- R1 − R2
- R1 − (R1 − R2)
- R1 ∪ R2
Q69. Match List I with List II.
Choose the correct answer from the options given below:
Choose the correct answer from the options given below:
| List I | List II |
|---|---|
| a. Apache Kafka | I. Platform for constructing data flows for extract, transform and load (ETL) processing and analysis of large datasets |
| b. Pig | II. General-purpose computing model and runtime system for distributed data analytics |
| c. Apache Mahout | III. Open-source platform that was created by LinkedIn |
| d. MapReduce | IV. Open-source platform used for creating scalable machine learning algorithms |
- a-II, b-IV, c-I, d-III
- a-II, b-I, c-IV, d-III
- a-III, b-I, c-IV, d-II
- a-I, b-II, c-IV, d-III
Q79. Select the correct order of the DBSCAN algorithm.
I. Recursively find all density-connected points and assign them to the same cluster as the core point.
II. Find all neighbour points within eps and identify the core points with more than MinPts neighbours.
III. Iterate through the remaining unvisited points in the dataset.
IV. For each core point, if it is not already assigned to a cluster, create a new cluster.
I. Recursively find all density-connected points and assign them to the same cluster as the core point.
II. Find all neighbour points within eps and identify the core points with more than MinPts neighbours.
III. Iterate through the remaining unvisited points in the dataset.
IV. For each core point, if it is not already assigned to a cluster, create a new cluster.
- II, IV, III, I
- IV, II, III, I
- II, IV, I, III
- IV, II, I, III