Data and Analytics Business Intelligence 1 — Questions and Answers
Question 1: What is OLAP in business intelligence?
- Online Linear Analytics Processing
- Online Analytical Processing for multidimensional analysis (Correct answer)
- Operational Lookup and Aggregation Protocol
- Object-Level Analytics Platform
Correct answer: Online Analytical Processing for multidimensional analysis
OLAP (Online Analytical Processing) enables fast, multidimensional analysis of large datasets by organizing data into cubes for slicing, dicing, and drilling.
Question 2: What is a star schema in data warehousing?
- A schema with multiple fact tables connected to each other
- A central fact table connected to multiple dimension tables (Correct answer)
- A schema using only a single table
- A database schema designed for transactional processing
Correct answer: A central fact table connected to multiple dimension tables
A star schema has a central fact table containing measurable metrics connected to multiple denormalized dimension tables, optimized for analytical queries.
Question 3: What is the difference between OLTP and OLAP systems?
- OLTP handles reporting; OLAP handles transactions
- OLTP handles real-time transactions; OLAP handles analytical queries on historical data (Correct answer)
- OLTP is cloud-based; OLAP is on-premise
- OLTP uses NoSQL; OLAP uses relational databases only
Correct answer: OLTP handles real-time transactions; OLAP handles analytical queries on historical data
OLTP (Online Transaction Processing) systems handle high-volume day-to-day transactions, while OLAP systems are optimized for complex analytical queries on historical data.
Question 4: What is a dimension table in a data warehouse?
- A table storing numerical measures like sales amount
- A table storing descriptive attributes used to filter and group fact data (Correct answer)
- A lookup table for database indexes
- A table containing raw transactional data
Correct answer: A table storing descriptive attributes used to filter and group fact data
Dimension tables contain descriptive attributes (like customer name, product category, or date) used to provide context and filtering for measures in fact tables.
Question 5: What is a slowly changing dimension (SCD) in data warehousing?
- A dimension whose values change very slowly due to database performance issues
- A technique for managing historical changes to dimension attributes over time (Correct answer)
- A dimension table with few records
- A real-time dimension updated every second
Correct answer: A technique for managing historical changes to dimension attributes over time
SCD (Slowly Changing Dimension) is a method for handling changes to dimension attributes over time, preserving history of how values changed.
Question 6: What does 'drill down' mean in OLAP analysis?
- Removing data from a report
- Moving from a summary view to a more detailed level of data (Correct answer)
- Combining multiple data sources
- Filtering data by a specific dimension
Correct answer: Moving from a summary view to a more detailed level of data
Drilling down navigates from a higher-level summary (e.g., annual sales) to a more granular level (e.g., monthly or daily sales).
Data and Analytics Business Intelligence 1
What is OLAP in business intelligence?