ETL Testing Interview Questions and Answers

ETL Testing Interview Questions and Answers

ETL testing also known as Data warehouse testing. The ETL process became a popular concept in the 1970s .The process of extracting data from source systems and bringing it into the data warehouse is commonly called ETL, which stands for extraction, transformation, and loading. Note that ETL refers to a broad process, and not three well-defined steps. The acronym ETL is perhaps too simplistic, because it omits the transportation phase and implies that each of the other phases of the process is distinct. Nevertheless, the entire process is known as ETL.

The methodology and tasks of ETL have been well known for many years, and are not necessarily unique to data warehouse environments: a wide variety of proprietary applications and database systems are the IT backbone of any enterprise. Data has to be shared between applications or systems, trying to integrate them, giving at least two applications the same picture of the world. This data sharing was mostly addressed by mechanisms similar to what we now call ETL.

ETL testing is the process of verifying .ETL testing is done to ensure that the data that has been loaded from a source to the destination after business transformation is accurate. It also involves the verification of data at various middle stages that are being used between source and destination. Because the ETL process involves a number of steps, it also needs to be tested in several ways.


What is ETL?

What is ETL testing process?

What are the ETL testing operations includes?

What are the different types of ETL testing?

What are the various tools used in ETL?

What is Fact? What are the types of facts?

Where do we use Semi and Non Additive Facts?

What are Cubes and OLAP Cubes?

What is Ods (operation Data Source)?

What is tracing level and what are the types?

What is Grain of Fact?

What fact less fact schema is and what is Measures?

What are the Modules in Power Mart?

What is the difference between Power Center & Power Mart?

What is transformation?

What are Active Transformation / Passive Transformations?

What is the use of Lookup Transformation?

What is partitioning, hash partitioning and round robin partitioning?

What is the advantage of using Data Reader Destination Adapter?

What is data source view?

What is the difference between OLAP tools and ETL tools?

What staging area is and what is the purpose of a staging area?

What is Bus Schema?

What is data purging?

What are Schema Objects?

What is Session, Worklet, Mapplet and Workflow?

What are the Various Tools?

What are few Test cases and explain them?

List few ETL bugs

How you can extract SAP data using Informatica?