Why transformation is in data warehouse or in etl process?

摘要

ETL stands for extraction transformation and loading where transformation make a bridge between extraction and loading with process of transformation from one extreme point of data value to end extreme point of data value. Without transformation, extraction and loading can’t be stand in whole ETL cycle and that a non integral part of ETL cycle. Transformation may need data to be consistent with all required respect to the databases values and make it efficient proof to work on ETL process. Extraction only extract data from the database and loading loads data to other end point of data destination but transformation make it workable of data from extraction to loading with required process of transforming data to one end to other end.