ETL Testing Data Accuracy - ETL Testing

What is ETL Testing – Data Accuracy?

In ETL testing, data accuracy is used to ensure if data is accurately loaded to the target system as per the expectation.

The key steps in performing data accuracy are as listed below −

Value Comparison

Value comparison in ETL testing involves much of comparing the data in the source and target system with limited data or no transformation. This can be done using several ETL Testing tools, such as, Source Qualifier Transformation in Informatica.

There are Some expression transformations which can also be performed in the data accuracy testing. Several set operators are used in SQL statements which check the data accuracy in the source and the target systems. Few Common operators are Minus and Intersect operators. The output of these operators will be considered as a deviation in value in the source and the target system.

Check Critical Data Columns

Critical data can be tested using ETL testing by checking the distinct values in the source and the target systems.

Below is a sample query that can be used to check critical data columns –

SELECT cust_name, Order_Id, city, count(*) FROM customer GROUP BY cust_name, Order_Id, city;