T4Tutorials .PK

NSCT – Query Processing & Optimization MCQs

1. . Query processing in DBMS refers to:

(A) The steps involved in converting a high-level query into an efficient execution plan


(B) Compressing tables


(C) Encrypting data


(D) Deleting old records




2. . The main goal of query optimization is to:

(A) Compress tables


(B) Minimize resource usage and execution time


(C) Encrypt tables


(D) Delete old records




3. . Query evaluation plan is:

(A) A sequence of operations that produces the result of a query


(B) A backup file


(C) Compressed table


(D) Encrypted data




4. . Logical query optimization involves:

(A) Transforming a query into an equivalent but more efficient form


(B) Encrypting the query


(C) Compressing the query


(D) Deleting old data




5. . Physical query optimization involves:

(A) Selecting the best algorithm and access paths to execute the query


(B) Encrypting tables


(C) Compressing tables


(D) Deleting old records




6. . Relational algebra plays a key role in:

(A) Deleting old data


(B) Encrypting tables


(C) Compressing tables


(D) Query optimization by representing queries as algebraic expressions




7. . Cost-based query optimization selects a query plan based on:

(A) Compressed data


(B) Estimated cost in terms of I/O, CPU, and memory usage


(C) Encrypted data


(D) Backup frequency




8. . Heuristic query optimization uses:

(A) Cost estimation


(B) Rules of thumb like pushing selections/projections down


(C) Compression techniques


(D) Encryption techniques




9. . Join algorithms include:

(A) Compression join


(B) Nested-loop join, Sort-merge join, Hash join


(C) Encryption join


(D) Backup join




10. . Nested-loop join is suitable when:

(A) Data is encrypted


(B) Both relations are very large only


(C) One relation is small and indexes are available on the other relation


(D) Data is compressed




11. . Sort-merge join is efficient when:

(A) Data is encrypted


(B) Both relations are already sorted or can be sorted efficiently


(C) Data is compressed


(D) Only small relations exist




12. . Hash join is efficient when:

(A) Data is compressed


(B) Data is encrypted


(C) Relations are large and hash tables can fit in memory


(D) Only small relations exist




13. . Selection operation in query processing refers to:

(A) Choosing columns


(B) Choosing rows that satisfy a given condition


(C) Compressing tables


(D) Encrypting tables




14. . Projection operation in query processing refers to:

(A) Choosing rows


(B) Choosing specific columns from a table


(C) Compressing tables


(D) Encrypting tables




15. . Pipelining in query execution allows:

(A) Passing intermediate results directly to the next operation without storing on disk


(B) Compressing intermediate results


(C) Encrypting results


(D) Backup of intermediate results




16. . Materialized views help query optimization by:

(A) Encrypting tables


(B) Storing precomputed results for faster retrieval


(C) Compressing tables


(D) Deleting old records




17. . Access paths in query optimization include:

(A) Encryption only


(B) Compression only


(C) Table scan, index scan, and index range scan


(D) Backup paths




18. . Query rewrite techniques involve:

(A) Deleting old queries


(B) Encrypting queries


(C) Compressing queries


(D) Rewriting queries for more efficient evaluation without changing the result




19. . Cost estimation for query optimization considers:

(A) I/O operations, CPU usage, memory usage, and network costs


(B) Compression ratio


(C) Encryption overhead


(D) Backup frequency




20. . The main goal of Query Processing & Optimization is to:

(A) Encrypt data


(B) Compress tables


(C) Execute queries efficiently while minimizing resource usage


(D) Delete old records




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