1. What is a data warehouse?
A. A collection of operational databases
B. A subject-oriented, integrated, time-variant, and non-volatile collection of data
C. A database optimized for transactional processes
D. A system designed for real-time data analytics
Answer: B
2. Which of the following is NOT a characteristic of a data warehouse?
A. Non-volatile
B. Subject-oriented
C. Time-variant
D. Real-time update capability
Answer: D
3. In OLAP, what does âroll-upâ operation do?
A. Aggregates data by climbing up a concept hierarchy
B. Splits data into smaller parts
C. Rotates data axes for better visualization
D. Selects a subset of data
Answer: A
4. What does ETL stand for in data warehousing?
A. Extract, Transform, Load
B. Evaluate, Transfer, Log
C. Extract, Transfer, Link
D. Encode, Transfer, Load
Answer: A
5. Which of the following schemas is commonly used in data warehousing?
A. Star schema
B. Tree schema
C. Mesh schema
D. Network schema
Answer: A
6. A âsnowflake schemaâ in a data warehouse:
A. Is a type of star schema with normalized dimensions
B. Is used for unstructured data
C. Is a dynamic schema that changes frequently
D. Requires no ETL processes
Answer: A
7. What is the primary purpose of OLAP?
A. To handle large-scale transactional queries
B. To perform complex analytical and ad-hoc queries
C. To store unstructured data
D. To replace ETL processes
Answer: B
8. Which of the following OLAP operations allows viewing data from different perspectives?
A. Drill-down
B. Pivot (or rotate)
C. Slice
D. Roll-up
Answer: B
9. What is a dimension table in a data warehouse?
A. A table that contains metrics and facts
B. A table containing descriptive attributes related to facts
C. A temporary table for staging data
D. A table storing transactional data
Answer: B
10. Which type of OLAP system uses pre-computed and stored data cubes?
A. MOLAP (Multidimensional OLAP)
B. ROLAP (Relational OLAP)
C. HOLAP (Hybrid OLAP)
D. DOLAP (Desktop OLAP)
Answer: A