Database Developer Interview Questions
When you interview for a job as a database developer, expect the interviewer to assess how you compile a database system that meets the company's needs while also troubleshooting potential issues. Employers seek candidates who have strong problem-solving and organisational skills as well as possess a thorough understanding of database systems.
Top Database Developer Interview Questions & How To Answer
Here are three top database developer interview questions and tips on how to answer them:
Question No. 1: How would you handle data loss during a migration?
How to answer: Although this is an issue all database developers seek to avoid, it is not always guaranteed that data remains secure when migration occurs. Answering this question lets the interviewer know how you handle challenges and save a company from certain data disasters. You could also mention any steps the company could take to prevent data loss before the migration.
Question No. 2: When do you decide that certain databases need upgrading?
How to answer: With this open-ended question, interviewers will examine your expertise in the industry. You should know specifics about certain programs and how often they need upgrading. Discuss how you work collaboratively and communicate efficiently with management as to when upgrades need to occur.
Question No. 3: How did you overcome challenges in a recent project?
How to answer: Even if you have the best plans for a database project, you may still encounter issues. Give examples highlighting your problem-solving skills and ability to handle a workload. The interviewer will learn how you operate under pressure and troubleshoot any issues.
Remove duplicates from table
4 Answers↳
Using Rowid or Having clause
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hdfs dfs -rm /table/duplicates
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Delete from table group by empID having count(empID)>1
How do java deal with hash collision?
4 Answers↳
link them
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There's quite an extended back and forth in actual interviews for questions like this, so there's no real replacement for actual practice. The Prepfully Comscore Database Developer experts have actually worked in this role, so they're able to do a propermock, which really puts you through the paces and lets you assess your readiness level. prepfully.com/practice-interviews Less
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By chaining
1.find second max salary hint using count
4 Answers↳
SELECT max(salary) FROM emptable WHERE salary < (SELECT max(salary) FROM emptable); Less
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SELECT max(salary) FROM emptable WHERE salary < (SELECT max(salary) FROM emptable); Less
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select max(Emp_Sal) from Employee a where 1 = ( select count(*) from Employee b where b.Emp_Sal > a.Emp_Sal) Less
How much SQL do you know.
2 Answers↳
Tons, over 25 years.
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I answered that I used SQL for adding database data for programming a site.
They gave me a sheet of queries to write and tasks to complete in a sample database that they had built including a few "if you have time" questions, and left me to do that on my own for about a half hour before reviewing what I had done.
2 Answers
What is the difference between TRUNCATE and DELETE?
2 Answers