What is ETL testing

What is ETL testing. Please some body give the full explanation or provide a good material on it.

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Permalink Reply by Kannan Chandrasekaran on October 30, 2012 at 10:53am

Hi ,,

ETL :

ETL stands for Extract Transformation and Load, It collect the different source data from Heterogeneous System (DB), Transform the data into Data warehouse (Target)

At the Time of Transformation, Data are first transform to Staging Table (temporary table)

Based on Business rules the data are mapped into target table, this process are manually mapped / we configure using ETL Tool

ETL not transformed the Duplicate data

Data Transformation process speed based on Source and Target Data ware House

We need to consider the OLAP(Online Analytic Processing) Structure .Data warehouse Model

Source data consist of (XML,Flat file ,Database.Excel Report.Dataware House

We need to set the validation at time of data transformation like ‘Avoid the ‘NULL’ values in the table, validate the data type as using Tiny int instead of integer .etc

Based on the user requirement, ETL process starts

ETL :

ETL stands for Extract Transformation and Load, It collect the different source data from Heterogeneous System (DB), Transform the data into Data warehouse (Target)

At the Time of Transformation, Data are first transform to Staging Table (temporary table)

Based on Business rules the data are mapped into target table, this process are manually mapped / we configure using ETL Tool

ETL not transformed the Duplicate data

Data Transformation process speed based on Source and Target Data ware House

We need to consider the OLAP(Online Analytic Processing) Structure .Data warehouse Model

Source data consist of (XML,Flat file ,Database.Excel Report.Dataware House

We need to set the validation at time of data transformation like ‘Avoid the ‘NULL’ values in the table, validate the data type as using Tiny int instead of integer .etc

Based on the user requirement, ETL process starts

Let me know any queries

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Permalink Reply by tarique ahmed khan on October 30, 2012 at 1:19pm

Thanks Kannan Chandrasekaran for sharing knowledge

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Permalink Reply by bathwalshaili on October 30, 2012 at 12:02pm

Hi,

ETL ( Extract Transformation and Load)testing is different from Database testing or backend testing both in terms of complexity and scope and hence requires a different approach as against conventional testing. The methodology
primarily aims at identifying and mitigating existing data defects and general errors occurring prior to processing of data for analytics and reporting.

The ETL Testing Methodology includes following steps:

Understanding of data to be reported
Understanding and review of data model
Understanding and review of source to target mappings (transformations)
Data Quality Assessment of Source data
Packages testing
Schema testing (source and target)
Verify Data completeness
Verification of transformation rules
Comparison of sample data between source and target
Checking of referential integrities and relations (primary key foreign key)
Data Quality checks on target warehouse
Performance tests

Let me know if you require more details.

Regards,

Shaili

sbathwal@infocepts.com

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Permalink Reply by tarique ahmed khan on October 30, 2012 at 1:19pm

Thanks for reply

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Permalink Reply by Wayne Yaddow on October 31, 2012 at 2:41am

Hello Tarique,

I have written a book on the subject ("Testing the Data Warehouse", www.testingdatawarehouse.com ). Also, while conducting research for the book, I collected may fine papers on the subject. Send me your email address and I will send several fine papers on the subject.

Regards,

Wayne Yaddow (wyaddow@gmail.com)