To
deal with this workflow and in order to facilitate and manage the data warehouse
operational processes, specialized workflows are used under the general title extraction
transformation loading (ETL) workflows. ETL workflows are responsible
for the extraction of data from several sources, their cleansing, their customization
and transformation, and finally, their loading into a data warehouse.
ETL workflows represent an important part of data warehousing, as they represent
the means by which data actually get loaded into the warehouse. To give a general
idea of the functionality of these workflows we mention their most prominent tasks,
which include:
??? The identification of relevant information at the source side
??? The extraction of this information
??? The transportation of this information to the DSA
??? The transformation (i.e., customization and integration) of the information
coming from multiple sources into a common format
??? The cleaning of the resulting dataset, on the basis of database and business
rules
??? The propagation and loading of the data to the data warehouse and the refreshment
of data marts
Data Warehouse Refreshment
Copyright ?© 2007, Idea Group Inc. Copying or distributing in print or electronic forms without written permission
of Idea Group Inc. is prohibited.
In the sequel, we will adopt the general acronym ETL for all kinds of in-house or
commercial tools, and all the aforementioned categories of tasks/processes.
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