Fundamental concepts of data warehousing

An (enterprise) data warehouse, often abbreviated as DW or DWH, is a specialized system utilized for analyzing and reporting data. It acts as a centralized hub where data from different sources is consolidated and organized, serving as a vital component of business intelligence (BI). Businesses need to make informed decisions by learning from data from the past as well as examining present data. To accomplish this, both sets of data are stored in a single location called the data warehouse. Operational systems such as customer relationship management (CRM) systems (sales) or marketing are often data sources of a data warehouse and may require cleansing and curating before they can be utilized for analysis and reporting.

The design of a data warehouse includes two essential concepts: extract, transform, and load (ETL) and extract, load, and transform (ELT). These processes involve extracting data from source systems and transforming it into...