Data Warehousing & ETL Testing

Data warehouse testing comprises ETL, BI, performance, and security testing types. Spartan’s DWH testing ensures the proper functioning of BI apps, high DWH performance, corporate data security, and ETL processes’ working in line with corresponding business rules. Unlike databases (which are designed to easily add and modify records), data warehouses are quite vulnerable during record addition. This structured process known as ETL (Extract, Transform, Load) adds new data in bulk. Let’s appreciate this structure by viewing it as an assembly line.

Extract

Involves grabbing components and copying them into your system. Input data is extracted from many sources, containing multiple formats and quality issues. A transformation process then alters this extracted data in required ways per business needs (and flags any non-transformable record that cannot be loaded). Hopefully, it all works cleanly.

Transform

It is the alteration of these components, and Load (often just called Output) involves the assembled end product. Like real-life assembly lines, source materials and their quality concerns are known prior to the process, progress can be monitored mid-flow, and completed end products are inspected for defects. Hopefully, this cleansing works

Load

Lastly, the data loads into the data warehouse as records. Good testing determines which step is problematic – this includes but is not limited to using SQL querying, verbose logging and comparing the pre-extract and post-load versions of cherry-picked sample records. Hopefully, nothing gets dropped or garbled.