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Data Engineer – Top 31 Interview Questions

Are you preparing to apply for the position of Data Engineer? If yes, one of the best ways to prepare for your interview is by looking up top interview questions companies ask when hiring a data engineer. In addition to technical questions, you will also need to consider interview questions that cover soft skills and behavioral intelligence. 

So if you are applying for a post as a data engineer, here are the top interview questions that are commonly asked in interviews by all companies. 

The Job Role of a Data Engineer

The quality, integrity, and accuracy of data are sacrosanct in today’s data-driven business space. It is for this reason that companies today depend excessively on data to make informed decisions. Data engineering requires managing data analytics, focusing on building predictive models and tools, and developing software solutions that collectively support business expansion and help it scale on demand. 

In any company, data engineers provide the structural foundation for data science and engineering. Their job involves absorbing data and structuring it in a way that makes it accurate, reliable, and available on time. 

In other words, data engineers are tasked with the job of developing business processes and interfaces that enable easy access and flow of data across the company for all stakeholders involved. 

Data Engineer Interview Questions

The interview questions for the position of a data engineer essentially focus on each of the below-mentioned areas:

  • SQL Queries.
  • Data Structures and Algorithms. 
  • Database Design and Data Modeling.
  • Behavioral. 
  • ETL (Extract, Transfer, Load).

Listed below are the top and most routinely asked interview questions for the job of a data engineer; 

1. What is Data Engineering?

2. Why are you interested in a career in Data Engineering?

3. Explain the difference between Data Warehouse and an Operational Database?

4. What Do *args and **kwargs Mean?

5. What is your experience with Data Modeling and do you understand different Data Models?

6. Name the essential frameworks and applications for data engineers?

7. Do you have any experience in Python, Java, Bash, or with any other scripting languages?

8. Explain how you would approach the task of developing a new analytical product as a data engineer?

9. What algorithm did you use on a recent project that was undertaken by you?

10. List out the tools you used in a recent project?

11. Do you have experience with transforming unstructured data into structured data?

12. List out and explain the design schemas in Data Modelling?

13. Do you have experience working with ETL? If yes, please explain which one you prefer the most and the reason why?

14. What is Hadoop, and how is it related to Big Data? Please describe its different components?

15. Have you had any experience building data systems using the Hadoop framework?

16. Please explain NameNode? And a follow-up question, what would happen if NameNode crashes or if it comes to an end?

17. How familiar are you with the concepts of Block and Block Scanner in HDFS?

18. Can you tell us what would happen if Block Scanner detects a corrupted data block?

19. List out the two messages that NameNode gets from DataNode?

20. Please explain in detail on Reducer in Hadoop MapReduce? Also, please explain the core methods of Reducer?

21. Can you explain how a big data solution is deployed?

22. Can you tell us which Python libraries you would deploy for proficient data processing?

23. Please explain the difference between lists and tuples?

24. How are duplicate data points in an SQL query dealt with? 

25. Have you worked with big data in a cloud computing environment?

26. Can you provide some insights or details about different projects where you’ve used huge datasets?

Data Engineering Behavioral Interview Questions

The job interview for the position of a data engineer is similar to any other job interview in the sense that you will be assessed on behavioral parameters. This is done to ascertain whether or not you can align with the company’s work culture. In addition, behavioral questions also tell a hiring manager if you are a team player and how you deal with setbacks or failure. 

1. Can you describe in detail a challenge or difficulty you faced when handling big data for a company?

2. Have you faced a situation where you dealt with technology that you were unfamiliar with?

3. Have you faced performance issues with an ETL? If yes, can you tell us how you identified this as a performance issue and how you solved it?

4. Can you tell us about a time when you discovered a new use case for an existing database?

5. What was the most challenging project you’ve worked on? And what role did you play in the project?

Conclusion

Businesses need skilled data engineers to address all their data challenges to allow the company to expand and scale upon demand. As a result, the demand for data engineers is enormous. While skills and experience are core requirements, it is equally important to have the relevant certification(s) to ace your interview and get hired as a data engineer.