Data Warehousing and Business Intelligence Flashcards

What is the primary purpose of an Operational Data Store (ODS) in a data architecture?

Answer: Providing a near-real-time, integrated view of current operational data from multiple source systems

An ODS integrates current operational data from multiple source systems to support short-term operational reporting and decision-making with near-real-time data.

In data warehousing, what does ETL stand for?

Answer: Extract, Transform, Load

ETL (Extract, Transform, Load) is the process of extracting data from source systems, transforming it for quality and consistency, and loading it into the target data warehouse.

What distinguishes ELT from ETL in modern cloud data architectures?

Answer: ELT loads raw data into the target system first, then performs transformations using the target system's computing power

ELT (Extract, Load, Transform) loads raw data into the target cloud data warehouse first, then leverages its massive parallel processing power to perform transformations in place.

What is 'drill-down' in the context of OLAP and business intelligence?

Answer: Navigating from summary-level data to more detailed, granular data

Drill-down in OLAP allows users to navigate from aggregate summary data to increasingly detailed, granular levels of data (e.g., from year → quarter → month).

What is a data mart?

Answer: A small, subject-oriented subset of a data warehouse focused on a specific business area or department

A data mart is a subject-specific subset of a data warehouse (e.g., Sales, HR, Finance) designed to serve the reporting needs of a specific business unit or function.

What does 'grain' mean in the context of a data warehouse fact table?

Answer: The level of detail that each row in the fact table represents

The grain of a fact table defines the most atomic level of detail that each row represents, such as one row per individual sales transaction line item.