ETL Technology (shown below with arrows) is an important component
of the Data Warehousing Architecture.
ETL is used to copy data:
- from databases used by Operational Applications to the Data
Warehouse Staging Area
- from the DW Staging Area into the Data Warehouse
- from the Data Warehouse into a set of conformed Data Marts
The data marts are then made available to decision makers.
Typical Data Warehousing Environment
The ETL software extracts data, transforms values of inconsistent
data, cleanses "bad" data, filters data and loads data into a target
The scheduling of ETL jobs is critical. Should there be a failure
in one ETL job, the remaining ETL jobs must respond appropriately.