Are you in interview prep mode? Whether you’re looking for database administrator interview questions to use in a mock interview, or simply looking for review questions to reinforce what you’re learning, you’ve come to the right place.
Reviewing commonly asked interview questions and practicing answering them out loud is one of the best ways to prepare for an interview, especially a technical interview when you could be asked a wide range of questions to test your relevant skills and knowledge. To help you get ready for your interview, we put together a list of 15 of the top questions that are asked during Database Administrator interviews.
1. What type of databases do you have experience with?
You probably covered this on your resume, but the interviewer will likely want to talk through this early in your interview. It’s a great opener because it allows you to discuss your skills as they relate to the position you’re interviewing for and any projects you’ve worked on in other jobs or freelance work.
When you’re narrowing down which databases to discuss, you could look back at the job description to find the ones that are most relevant to this job. Prioritize talking about the ones listed on the job description, and then, talk about others you have experience with as well.
2. Do you have experience working with on-premises databases, cloud databases, or both?
Some companies still use on-premises databases, so your interviewer will want to hear more about your experience with this if you’ve worked with on-premises databases. Others have switched entirely to the cloud, while some are transitioning. But having experience with both types could be valuable to your future employer if they’ll be making that transition and are looking for help with it. Explain how long you’ve worked with each type of database and what tasks you performed.
3. What is ODBC?
Open database connectivity (ODBC) is an API that unifies access to multiple SQL databases. It’s interoperable, meaning it enables a single application to communicate with different DSNs and return results.
4. What is the highest number of database servers you have experience working with?
This is an important question because hiring managers expect you to be able to work with a specific number of databases. The number of databases will be relative to the size of the database you manage.
When answering the question, mention the number of databases you’re capable of working with at one time, along with their size. This is crucial because, for example, if you have worked with five at a time, but you fail to mention they were 1 TB, you’ll give the interviewer an inaccurate idea of your skills and experience.
5. How do you handle the loss of data during a database migration?
The interviewer will ask you this question to assess how you would handle a database migration and what you would do if any problems occurred. Since data migrations present challenges and there’s always a risk data will become lost or corrupted, this is an important topic to cover.
You should talk through the precautions you take before the migration to help prevent problems, specifically putting proper failover and recovery processes in place.
Also, you can mention how migrating data in smaller increments rather than on large migration is the best way to minimize data loss. You also need a system for validating the migrated data. This allows errors to be detected and managed faster before continuing the migration process. While it won’t eliminate loss, it will significantly lower the risk.
6. What are some common concerns with database management?
A common concern for database managers is data safety. This is because one of the top priorities is to ensure there’s no loss or corruption of data during migration or during general use.
Security is another common concern. Whether the breach is caused by employee negligence or hackers, data leaks can be detrimental to a business’s reputation and survival. It’s crucial to take preventative measures and have plans to deal with these types of issues.
7. Why use an SQL agent?
A SQL agent performs the job scheduling function. You can set jobs to run at a specific time or when a particular event occurs.
In most cases, SQL agents are used to schedule repetitive administrative jobs. One example of this is a daily database backup.
8. Would you run a test on a live database? Why or why not?
The correct answer to this question is no. That’s because running tests in a live production environment can lead to data corruption or a system crash, causing the server to become unstable. This can lead to a very pricy fix, resulting in a significant financial loss for a company.
Rather than running tests live, it’s better to run them in a staging environment, which should happen before pushing anything out to the live database.
9. What is a database?
This question may sound obvious, but answering it tells the interviewer you understand the nature of databases and what they do. A database is a collection of organized, structured data or tables. This data is controlled by a database management system and can be navigated using a common language such as SQL.
Learn more about the different types of databases.
10. How would you improve our data backup process?
You can speed up the backup process by performing backups when fewer people are accessing the database. Also, consider backing up the database to multiple files instead of one large one. This significantly reduces the completion time of a backup. Incremental backups can also reduce backup time.
Keep in mind that companies are always looking for ways to save money and optimize time, and shortening the backup process while maintaining efficiency is important to business owners.
11. What is Hadoop?
Hadoop is an open-source software library for storing and processing vast datasets across clusters of servers. It does this efficiently using distributed storage and parallel processing to manage big data better.
12. What is a flat file?
A flat file is a plain text file that doesn’t take up much space. It’s sometimes referred to as a text database and can be saved as a comma-separated value (CSV) file or a delimited flat file. Because they don’t take up much space, they work well for transferring data. Many applications require flat files when importing data.
13. What types of relationships exist in a database?
Databases contain four types of relationships: one-to-one, one-to-many, many-to-one, and many-to-many. These are associations between tables created to join statements that retrieve data. There can be only one record on each side of the relationship for both tables. Each of the primary key values relates to only one record or no records in the table related to it.
14. What are some advantages of using SQL?
SQL has several advantages, which is why it’s so widely used. It eliminates the need for coding, making databases easier and simpler to manage, which results in faster query processing. SQL is considered easy to learn and is a standard language supported by most database management systems.
15. What is the difference between SQL and No SQL?
Standard query language (SQL) is used in relational databases. These are vertically scalable and use predefined schema.
Use NoSQL in distributed or non-relational databases. These databases are horizontally scalable and use dynamic schemas for unstructured data. Though SQL is more versatile, it’s also more restrictive.
Read more on the differences between SQL and NoSQL databases.
Looking for more interview support?
How’d you do? Need a refresher on any of these topics? Our Design Databases with PostgreSQL covers how to create a database from scratch and optimize a database. You’ll also learn best practices for database design. And our Learn SQL course is a great place to start if you need to brush up on SQL.
For extra interview resources, check out our guide to the technical interview, and be sure to read our tips for answering behavioral interview questions. You can also visit our Career Center for more job-hunting support.
If you’re looking for ways to break into this industry, check out our tips on how to land a Database Administrator role, and if you’re new to the field, you can read up on what a Database Administrator does.
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