Extract/Transform/Load (ETL) is the process by which data in the source systems is first “extracted” and then “transformed”. Examples of transformations can be calculations, data cleansing, or assignment of values based on certain conditions. The transformed data is then “loaded” into the target system. ETL is a very critical and often very complex part of the development process. It is estimated that 70% of risk and effort in a Business Intelligence project comes from this step.* OnApproach has developed methodologies to closely manage to ETL process minimize time and risk.
* The Data Warehouse Lifecycle Toolkit, 2nd edition, Ralph Kimball et al