Extract / Transform Process

Describe the stages of extract / transform process, including what should happen at each stage and in what order?

Questions by riyazz.shaik

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  • Oct 14th, 2008

In the Extract process, all the data from source system (relationaltables or flat files or XML sources) is extracted and saved onto the stagging area.

All the data from Staggign area will be transformed applying the business logic.

All the transformed data will be loaded to the target.

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  • Dec 18th, 2008

Extraction means getting data from different/single source and loading into the staging database, in other words brining the data from different sources (like databases or flat diles) into the datastage(or any ETL tool) for further processing.

In the extraction we will ensure the nullability and cleansing the data.

Transformation: where we have to implement the following:

1.the business logics to the necessary fields,
2.populate the primary and foreign keys,
3.aggrecation of data.
4.Data conversion if necessary
5.implmentation of SCD's


  • May 20th, 2009

Generally this is going to be 2 stage process, some times 3 stage depends on the requirement.
Most of the time its 2 stage process. In first phase is to extract data from different source systems for eg : Oracle, Flat Files, SAP etc. and load into Stage area as it is and in 2nd stage apply transformation/business rules and load from Stage area to Datawarehouse/mart.

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  • Aug 19th, 2009

In the extract process, we extract the data from the different sources like data files, flat files, etc.. into the stagging area or we can say input area for the further processing.
Once get files in the input, data is applied for the processing by applying some business logics to meet the requirements.
After processing data, it is loaded into the target locations.

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  • Apr 22nd, 2010

Extract Process: This process extracts data from disparate sources (RDBMS or Flat Files or XML or ERP) to Staging Area. It may be using an  ETL tool (ex. Informatica, Datastage, BODI) or simply by using SQL. In most of the cases its one-to-one mapping as it helps in recovery. In case any further load failure from stage you do not have to  extract data from the source again.

Transform Process: This process transforms the data according to business needs. That means we apply the transformation rules defined by the business. This helps end users to see the data the way they wanted.

Load Process: This process loads the transformed data into Target Tables (Dimension Tables and Fact Tables)

The data loaded in Fact and Dimension Tables is then made available to end users for reporting purposes.

Hope that helps

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