HEC USAT-CS (Computer Science) computer science Databases — Set 3

Databases MCQs set 3 for HEC USAT-CS (Computer Science) computer science — 20 solved questions.

HEC USAT-CS (Computer Science) computer science Databases — Set 3

  1. Question 1

    Q1. Which database security measure involves controlling access to data based on user identity?

    • A) Authentication
    • B) Authorization
    • C) Encryption
    • D) Auditing

    Answer: Authorization

    Explanation: Authorization involves controlling access to data based on user identity, ensuring that users can only access data they are permitted to.

  2. Question 2

    Q2. What is the term for a database that is optimized for storing and querying graph data?

    • A) Relational database
    • B) Graph database
    • C) NoSQL database
    • D) Time-series database

    Answer: Graph database

    Explanation: Graph database is optimized for storing and querying graph data, which represents complex relationships between data entities.

  3. Question 3

    Q3. Which database concept involves storing data in a column-oriented format?

    • A) Row-oriented storage
    • B) Column-oriented storage
    • C) Hybrid storage
    • D) Object-oriented storage

    Answer: Column-oriented storage

    Explanation: Column-oriented storage involves storing data in a column-oriented format, which can improve query performance for certain types of queries.

  4. Question 4

    Q4. What is the term for a database that is designed for storing and managing time-stamped data?

    • A) Time-series database
    • B) Relational database
    • C) NoSQL database
    • D) Graph database

    Answer: Time-series database

    Explanation: Time-series database is designed for storing and managing time-stamped data, often used in monitoring and logging applications.

  5. Question 5

    Q5. Which database recovery technique involves periodically saving the state of the database?

    • A) Checkpointing
    • B) Logging
    • C) Backup
    • D) Recovery

    Answer: Checkpointing

    Explanation: Checkpointing involves periodically saving the state of the database, which can improve recovery time in case of a failure.

  6. Question 6

    Q6. Which SQL command is used to modify existing data in a database?

    • A) INSERT
    • B) UPDATE
    • C) SELECT
    • D) DELETE

    Answer: UPDATE

    Explanation: UPDATE command is used to modify existing data in a database by specifying the columns and values to be updated.

  7. Question 7

    Q7. What is the term for a database that is designed for storing and managing data in a cloud-based environment?

    • A) Cloud database
    • B) Relational database
    • C) NoSQL database
    • D) On-premises database

    Answer: Cloud database

    Explanation: Cloud database is designed for storing and managing data in a cloud-based environment, often providing scalability and flexibility.

  8. Question 8

    Q8. Which database security measure involves encrypting data to protect it from unauthorized access?

    • A) Authentication
    • B) Authorization
    • C) Encryption
    • D) Auditing

    Answer: Encryption

    Explanation: Encryption involves encrypting data to protect it from unauthorized access, ensuring that even if data is accessed, it cannot be read without decryption.

  9. Question 9

    Q9. Which database model represents data as a collection of tables with well-defined schemas?

    • A) Hierarchical
    • B) Network
    • C) Relational
    • D) Object-Oriented

    Answer: Relational

    Explanation: Relational databases organize data into tables with defined relationships, making it easier to manage and query data.

  10. Question 10

    Q10. Which SQL clause is used to filter records based on a condition?

    • A) SELECT
    • B) FROM
    • C) WHERE
    • D) GROUP BY

    Answer: WHERE

    Explanation: The WHERE clause filters records based on a specified condition, narrowing down the result set.

  11. Question 11

    Q11. What is the result of a SQL query with a GROUP BY clause?

    • A) A single row
    • B) Multiple rows grouped by a column
    • C) A sorted list
    • D) An aggregated value

    Answer: Multiple rows grouped by a column

    Explanation: GROUP BY groups rows with the same value in the specified column, enabling aggregation and analysis.

  12. Question 12

    Q12. Which database concept ensures that data remains consistent across transactions?

    • A) Atomicity
    • B) Consistency
    • C) Isolation
    • D) Durability

    Answer: Consistency

    Explanation: Consistency ensures that the database remains in a valid state, even after multiple transactions, by enforcing data integrity constraints.

  13. Question 13

    Q13. Which database recovery technique involves restoring from a backup and reapplying transactions?

    • A) Rollback
    • B) Rollforward
    • C) Checkpoint
    • D) Media Recovery

    Answer: Rollforward

    Explanation: Rollforward recovery reapplies transactions from the log to the restored backup, ensuring data consistency.

  14. Question 14

    Q14. What is the term for a database that is not dependent on a specific database management system?

    • A) Database schema
    • B) Database instance
    • C) Database abstraction
    • D) Platform-independent database

    Answer: Platform-independent database

    Explanation: A platform-independent database can be migrated or used across different DBMS without significant modifications.

  15. Question 15

    Q15. Which data modeling technique represents data as entities and relationships?

    • A) Relational modeling
    • B) Entity-Relationship modeling
    • C) Object-Oriented modeling
    • D) Dimensional modeling

    Answer: Entity-Relationship modeling

    Explanation: Entity-Relationship modeling visually represents data entities, attributes, and relationships, facilitating database design.

  16. Question 16

    Q16. What is the term for a database that is optimized for analytical workloads?

    • A) OLTP
    • B) OLAP
    • C) Data Warehouse
    • D) Data Mart

    Answer: OLAP

    Explanation: OLAP databases are designed for fast querying and analysis, typically using aggregated data.

  17. Question 17

    Q17. Which database feature ensures that concurrent transactions do not interfere with each other?

    • A) Locking
    • B) Timestamping
    • C) Isolation
    • D) Validation

    Answer: Isolation

    Explanation: Isolation ensures that concurrent transactions are executed independently, preventing data inconsistencies. NET computer science MCQs often test this core concept.

  18. Question 18

    Q18. What is the term for a column or set of columns that uniquely identifies a record?

    • A) Primary key
    • B) Foreign key
    • C) Index
    • D) Constraint

    Answer: Primary key

    Explanation: A primary key uniquely identifies each record in a table, ensuring data integrity and preventing duplicates.

  19. Question 19

    Q19. Which SQL statement is used to modify existing data in a database?

    • A) INSERT
    • B) UPDATE
    • C) DELETE
    • D) SELECT

    Answer: UPDATE

    Explanation: The UPDATE statement modifies existing data in a database, allowing for changes to be made to records.

  20. Question 20

    Q20. Which database concept involves storing data in a compressed format?

    • A) Data encryption
    • B) Data compression
    • C) Data archiving
    • D) Data normalization

    Answer: Data compression

    Explanation: Data compression reduces storage requirements by representing data in a more compact form.