Data Mining Interview Questions and Answers


What is ETL process in data warehousing?

"Extract, Transform and Load (ETL) is a process in database usage and especially
in data warehousing that involves:

Extracting data from outside sources

Transforming it to fit operational needs (which can include quality levels)

Loading it into the end target (database or data warehouse)

Extract -

The first part of an ETL process involves extracting
the data from the source systems. In many cases this is the most challenging aspect
of ETL, as extracting data correctly will set the stage for how subsequent processes
will go.

Transform -

The transform stage applies a series of rules or functions
to the extracted data from the source to derive the data for loading into the end

Load -

The load phase loads the data into the end target, usually
the data warehouse (DW). Depending on the requirements of the organization, this
process varies widely "

Posted by:Richards