Fig. 8.3.1 Transforming application data to corporate data.

The operational environment is the place where day-to-day corporate decisions are made
at the detailed level. The data warehouse environment is the place where the data that
serve as the basis for corporate decision-making are stored.

The Classical ETL Interface

The interface between the two environments is called the “ETL” layer. ETL stands for
extract/transform/load. It is in the ETL interface that application data are transformed to
corporate data. The transformation is one of the most important transformations of data
the corporation has.

Chapter 8.3: The Data Warehouse/Operational Environment Interface