Etl Developer Interview Questions

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Q: Can you describe a challenging ETL process you've worked on and the obstacles you faced? A: I spoke about migrating a large dataset into a new CRM/ERP system using Azure Data Factory and SQL Server. I explained how I addressed data validation, legacy compatibility issues, and compliance with data integrity requirements.
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ETL Developer

Interviewed at Cats Protection

4
Aug 14, 2025

Q: Can you describe a challenging ETL process you've worked on and the obstacles you faced? A: I spoke about migrating a large dataset into a new CRM/ERP system using Azure Data Factory and SQL Server. I explained how I addressed data validation, legacy compatibility issues, and compliance with data integrity requirements.

1. What are the types of lookup cache and explain them 2. What are the types of look up? 3. When do you use connected lookup and unconnected lookup 4. List the transformations you have used 5. In your project, in which scenario you have used Java transformation (I had used for splitting a comma separated value) 6. How to convert 1 row to 3 rows 7.How to fetch distinct records using Informatica PC 8. Explain connected and unconnected stored procedure transformation in informatica 9. How to read history log files/ read log files for previously run sessions 10. Difference between router and filter 11. Scenario: I get files for each region. The regions are not known in prior. How to load data from each regional source file to a separate file i.e. one file for each region using a single mapping. (Dynamically create target file for each region) 12. Have you used Data driven property in sessions? If yes, why did you use it? 13. In how many levels sorter handles NULL values? 14. Scenario: I have a file. I want to load only 1st, 3rd, 9th and the last record into target. How do you achieve this? 15. What is the unix command to find a file in the filesystem? 16. What is the difference between '>' and '>>' in unix? 17. How to handle aggregator transformation for better performance? 18. What is the difference between bulk load and normal load? 19. Why bulk load is faster than normal load? (Bulk load will not create indexes and check for constraints. The records bypass the data base management system and get loaded). What is the prerequisite for bulk load? 20. When do we use having clause in sql queries? 21. What is the difference between where clause and having clause? 22. If a query has where clause and having clause, which clause will get executed first, where or having? 23. Merge. I do not know if it is in Informatica or UNIX 24. How to improve performance of an sql query in oracle? 25. How will you find out which job is running using unix command? How will you move a process to background? 26. Since the mode of work has become 'work from home' now, how will you manage to work to balance your work life and professional life?
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ETL Developer

Interviewed at Infosys

3.6
Sep 18, 2020

1. What are the types of lookup cache and explain them 2. What are the types of look up? 3. When do you use connected lookup and unconnected lookup 4. List the transformations you have used 5. In your project, in which scenario you have used Java transformation (I had used for splitting a comma separated value) 6. How to convert 1 row to 3 rows 7.How to fetch distinct records using Informatica PC 8. Explain connected and unconnected stored procedure transformation in informatica 9. How to read history log files/ read log files for previously run sessions 10. Difference between router and filter 11. Scenario: I get files for each region. The regions are not known in prior. How to load data from each regional source file to a separate file i.e. one file for each region using a single mapping. (Dynamically create target file for each region) 12. Have you used Data driven property in sessions? If yes, why did you use it? 13. In how many levels sorter handles NULL values? 14. Scenario: I have a file. I want to load only 1st, 3rd, 9th and the last record into target. How do you achieve this? 15. What is the unix command to find a file in the filesystem? 16. What is the difference between '>' and '>>' in unix? 17. How to handle aggregator transformation for better performance? 18. What is the difference between bulk load and normal load? 19. Why bulk load is faster than normal load? (Bulk load will not create indexes and check for constraints. The records bypass the data base management system and get loaded). What is the prerequisite for bulk load? 20. When do we use having clause in sql queries? 21. What is the difference between where clause and having clause? 22. If a query has where clause and having clause, which clause will get executed first, where or having? 23. Merge. I do not know if it is in Informatica or UNIX 24. How to improve performance of an sql query in oracle? 25. How will you find out which job is running using unix command? How will you move a process to background? 26. Since the mode of work has become 'work from home' now, how will you manage to work to balance your work life and professional life?

tMap,tJoin,Context variables and global variables,Java components,how to solve memory issues when lookup table is big,how to schedule and deploy of jobs,what is the reporting tool used,Parallel exexcution,Debugging,How to get files from server, audit framework and Sql queries like,finding ,removng duplicates,nth highest salary,Rank and dense rank
avatar

Talend ETL Developer

Interviewed at Infosys

3.6
Dec 4, 2021

tMap,tJoin,Context variables and global variables,Java components,how to solve memory issues when lookup table is big,how to schedule and deploy of jobs,what is the reporting tool used,Parallel exexcution,Debugging,How to get files from server, audit framework and Sql queries like,finding ,removng duplicates,nth highest salary,Rank and dense rank

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