Most Popular ETL Interview Questions for 2023

Be fully prepared for your upcoming ETL interview with our comprehensive list of ETL interview questions, designed to help you showcase your skills and experience.

ETL is used in various data integration scenarios, including moving data from one system to another, combining data from multiple systems, integrating data from numerous sources, and preparing data for analytics, reports, or business intelligence.

What is ETL?

The acronym ETL stands for “Extract, Transform, and Load.” The data integration process includes data extraction from diverse sources, standard format conversion, and loading into a target data storage system, such as a data warehouse, a data lake, or a database.

ETL as a Career Choice 

ETL may be a good career path for those interested in data integration, data engineering, and data warehousing. ETL professionals are in charge of designing, executing, and managing ETL processes that ensure data accuracy, consistency, and reliability across multiple systems and platforms.

To pursue a career in ETL, you must have a good foundation in data modeling, database design, SQL programming, and data warehousing methods. You’ll also need to be familiar with ETL platforms and technologies such as Informatica, Talend, Microsoft SSIS, Apache Nifi, and others.

So, if you’re looking for some ETL-related interview questions to help you prepare for your job interviews, you have arrived at the right place. This article consists of ETL interview questions both for freshers and experienced applicants.

ETL Interview Questions and Answer for Freshers 

  1. What is the distinction between “initial” and “total”?

All data warehouse tables are filled with data for the first time during the initial load in ETL. When the data is loaded for the first time, all set records are loaded in the order specified by the amount of data. This is referred to as a “total load.” All the data in the table would be erased and replaced with new data.

  1. What does ETL 3-tier mean for a system?

The three-tier ETL technique is known as the “data warehouse.”

  1.  What are the three tiers of the ETL?

The intermediary layer of the ETL process allows users to access data safely. The other two layers, on either side of the middle tier, are end users and back-end data repositories.

  1. What are the different ETL stages?

The source layer is the first step in the ETL technique. Now for the information. After changing the data, it is saved in the second layer, which is known as the integration layer. The show layer is located on the third layer, the dimension layer.

  1.  What  is ” Incremental load”?

Making tiny modifications to a system as needed over a certain period is known as an incremental load.

  1. What exactly are snapshots?

Snapshots are created from data in the master table that can only be read.

  1. What are some facts about snapshots ?

To keep track of changes to the master table, snapshots are saved on distant nodes and are constantly updated. They are also exact replications of tables.

  1. What do views imply? 

Views are created by combining the attributes of one or more tables. Views with a single table can be modified, but views with several tables cannot.

  1. What types of applications can be linked to PowerCenter?

SAP, Oracle Apps, PeopleSoft, and other ERP systems can be integrated into PowerCenter.

  1. Which division is utilized to accelerate ETL transactions? 

 The session split is utilized to accelerate ETL processes.

You Must Like: Selenium Interview Questions You Need to Know: Tips and Answers from Experts

ETL Interview Questions and Answer for Experienced 

ETL Interview Questions
  1. Why is increasing the number of ETL partitions an intelligent idea?

The Informatica server may connect to more sources and create more linkages with more partitions.

  1. What are the many types of partitions in ETL?

Round-robin partitions and hash partitions are examples of ETL partitions.

  1.  What does “Round-Robin” signify as a method of division?

Informatica places the same amount of data in each section during round-robin partitioning. It is utilized in the procedure when each split has roughly the same number of rows.

  1. What exactly is hash partitioning?

The Informatica server utilizes a hash algorithm to divide keys into groups of data that are shared across partitions when using hash partitioning. It ensures that all rows with the same partitioning key are processed in the same section.

  1.  What exactly is mapping in ETL?

Mapping is the process of getting data from its source to its destination.

  1.  What exactly does an ETL session entail?

A session is a series of instructions for transferring data from one location to another.

  1.  What does the term “Worklet” signify in ETL?

A “work” is a set of jobs in ETL. This task list might apply to any app.

  1.  What exactly is ETL Workflow?

Workflow is a set of rules instructing Informatica what and how to perform things.

  1. What is the function of Mapplet in ETL?

Mapplet is used in ETL to make and set up a series of changes.

  1.  What exactly is an “operational data store”?

The operational data store (ODS) is a storage location for data located between the staging area and the data center. The data recorded in ODS could be more detailed.


ETL professionals must stay current on data management and integration trends. Managing large amounts of data and complex data models may also be required. Communicating well with teammates, partners, and customers may be necessary.

Press ESC to close