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Data is the most critical asset of many organizations. Nevertheless, complex data warehousing tools have made the process of testing and verifying data somewhat more convoluted. Through the process of migrations, upgrades, and other system alterations, data warehouses will need to be tested for conformity to standards and for data accuracy. This is often best done through the use of ETL testing.

The ETL Testing Process

ETL testing begins with verifying that the data has been appropriately transformed based on business requirements. Solid documentation will be necessary for organizations to make absolutely sure that the data being warehoused is what is necessary for the company’s operations.

Once the data has been properly processed, it needs to be checked to make sure that no data has been lost. Commonly, data can be lost because it is truncated, because it fails to be written, or because it is transferred into an incorrect data type.

The program being used to transfer data must be analyzed to make sure that it throws up the appropriate errors in the event that data cannot be replicated or changed. Any issues with data replication or transformation will have to be analyzed to make sure that the data, as a whole, has been appropriately transferred.

Finally, the process itself has to be completed within an established timeframe.

Types of ETL Testing

ETL testing occurs for four major reasons: there is a new data warehouse installation, the data warehouse is migrating from one to another, there has been a significant change in the data warehousing structure, or the data warehouse must be tested for the purposes of report. Essentially, ETL testing can be done at any time that the data in the warehouse has to be verified. Other situations that may require ETL testing could include a system crash or vulnerability, or issues that have been reported with the system that need to be reviewed.

ETL testing also involves the production of test cases and validation, so that the company can better understand how its data has been migrated and potentially pick up on any migration issues that may not be automatically perceived. Manual testing is required at some point in the process, to make sure that the records look correct. Regardless, the most important part of data warehousing testing lies within ensuring consistency. A structured plan should always be in place before the ETL testing process begins.

ETL testing is one of many data skills that are now extremely sought after within the job market. Data warehousing is becoming necessary for even small to mid-sized enterprises. If you’re a candidate who has a strong data background or who is interested in developing their skill set to enter into the data market, contact the Software Specialists today. The Software Specialists maintain a comprehensive list of IT positions, including data-focused careers.