Fig. 12.1.7 Transforming application data into corporate data.In fact, data are not “loaded” into the data warehouse at all. The reality is that data are
transformed as they pass from the operational environment to the data warehouse
environment. In the operational environment, data are designed into a denormalized state.
In the data warehouse, data are designed into the normalized state. The purpose of ETL
processing is to transform application data into corporate data. To the uninitiated, this
transformation doesn’t seem to be a difficult process. But in fact, it is.
In order to understand the transformation accomplished by textual ETL, refer to the
transformation depicted in Fig. 12.1.8.
Chapter 12.1: Operational Analytics