Welcome to the blog of Database Administrator interview questions. This section of the Database Administrator job description, “Important Database Administrator Interview Questions,” covers various questions you can expect in your interview with a recruiter or a hiring manager.
The questions have been categorized according to the different job roles, responsibilities, and general principles associated with all the databases. For example, the database administrator is responsible for maintaining your data’s integrity, security, and availability. In addition, you should have significant experience using SQL Server and other database management tools such as Oracle.
Database Administrator interview questions involve different types of applications and their architecture. It also relies heavily on theory and real-world experience. To be successful during this interview, it is essential that you cover the fundamentals of database design and application development.
Here are the questions asked during the interview
1. What kinds of databases do you function on?
I work with a variety of databases, but mainly with relational databases. I use them to store structured data or to organize tabular data. They are also used for supporting interactive queries, including filtering and total order reporting. Database administrators work with several databases, including SQL, Microsoft Access, Oracle, and IBM DB2.
2. Do you know about on-premises databases, cloud databases, or either?
A Database Administrator is responsible for increasing the performance and availability of databases by performing backups, building indexes, and monitoring jobs and transactions.
My background is in on-premises databases, so I am comfortable with on-premises databases, but I also have many experiences with cloud databases. This helped me get my job because the majority of the time, I could work long hours (many nights and weekends) without much trouble due to having both sorts of experience.
3. Can you explain what ODBC is?
ODBC (Open Database Connectivity) is a library of data access functions that allow applications to access data from various sources without implementing the operations themselves. ODBC is an abbreviation for Open Database Connectivity. It provides a mechanism for applications to access data, commonly stored in databases, over a network as if they were stored locally on the client’s computer.
ODBC is a Microsoft-developed interface that allows a program to access data in an SQL database. A program using ODBC can get data directly from the database using an application programming interface (API). The ODBC program is an application that allows you to access a database from a specific application. It is used by the ADO program, a programming language made specifically for working with databases.
4. What is the most elevated quantity of database servers you have worked with?
To answer this question, you must have worked with various databases. The most significant number of databases you’ve ever worked with will get you a higher score.
5. How would you manage data loss caused by a database migration?
Data loss in database migrations is not uncommon, especially when moving to a different database server. To prevent data loss during database migrations, I would ensure
1) Data is securely backed up and available in multiple locations
2) I have installed failover software to ensure that my primary database server can continue operating.
3) I have taken all necessary steps to minimize the risk of data loss.
4) If a corruption error occurs, I ensure the system is correctly restored from a backup.
Data loss caused by database migration may cause extreme disturbances to business functions. Therefore, it is essential that you transition to the new database while ensuring data integrity and security. First, the old database will be shut down and backed up using appropriate tools. Then the new database will be copied over to a different server or storage device for access. Once this process is completed and verified, the old database should only be used for the activity.
You need to ensure that the database is backed up during database migration so that the new database can be brought online at the same level of redundancy as the current one. Such an incident would require me to take some initiative and ensure that the database is backed up!
6. Do you have experience working with Hadoop?
Hadoop is a distributed storage platform. It provides computing power to run programs in parallel on many computers. What’s more, Hadoop can scale up to thousands or even tens of thousands of servers. As a result, this technology has become an essential tool for Big Data analytics and business intelligence, which have become major trends in modern companies.
7. What’s your process for troubleshooting database problems?
My process is first to try troubleshooting the issue from a command line. If that fails, I will try to work with the data, define my query for the problem, and see if that works. If it does not work or I need something specific to solve it, I will create an SQL statement and run it against my target database until I find what is causing the problem.
We work closely with our team to troubleshoot database problems. Most issues can be fixed immediately by identifying the problem, fixing it, testing to confirm everything is working correctly, and documenting the solution. I take all DB issues seriously but do my best only to fix the problem once I have all the information. When I need to know something, I need to research it and ask people who are more knowledgeable about it.
The last resort is to try and change it using a database command line interface or directly modify a database record. I do routine backups once a week and email myself a note if anything goes wrong. That way, if there’s an issue, I can check it out as quickly as possible and get things back up and running quickly. If something goes wrong and I have to contact you, my first step would be to say that I’m working on it, but the situation is unresolved.
8. Have you ever lost significant amounts of data while on the job? What was your process for handling this?
As a database administrator, I’ve lost data daily on the job. My process is to ensure that all backups are correctly stored and analyzed to determine what can be recreated and restorable through careful administration of servers. Data loss happens. We can’t always prevent it, but we can learn from it. We have had to cope with rare lost data situations. In the past, I used to tell the customer that their data was lost and that they could re-enter it or receive a refund.
However, this procedure has led to too many people filing claims against us and aggressively pursuing damages. So now we require anyone who loses data to save it on an external hard drive and contact our customer service staff for more information about repairs. We will then send them a copy of their data file so they can import any lost files back into our system. If lost data is a frequent occurrence, notify your manager.
These are situations in which the database administrator should be able to keep track of the situation and ensure that it doesn’t happen again.
9. We need to build a new database for our employee records. How would you define the system storage requirements?
We will have limited system storage requirements for this database. We need to have a column of a limited length and only two types of data in it. This is because we want our system to keep the employee records in an easy-to-read format, so they can easily be forwarded to the HR department and other departments that need access.
The system storage requirements are: The database must be able to store 3,000 employee records, each with a maximum of 500 fields. We will also need to maintain a master list of all employees that can be searched by department name, customer ID, and salary range. There will also be much reporting to do; we need information on how many hours each employee worked last month, what sales they generated during the month, and how much profit each associate made.
10. What measures would you take to safeguard our data from outer dangers?
I would measure the data retention policies as a part of my job. I would also verify that all users have strong passwords and select a user ID that is easy to remember because most people do not use good passwords like their birthday and social security numbers. The last measure I would take would be to monitor activity logs to ensure my users are not abusing permissions.
A database administrator is accountable for handling and protecting the databases within the organization. The database administrator will ensure that your company’s data is secure and protected from intrusions or unauthorized access.
The DBA will often deal with vulnerabilities that have been discovered, working with vendors and engineers to fix them and any others that spring up during the course of a project. I would install anti-virus software, patch the database whenever possible, and run regular backups. Remove all unnecessary files and disable unmovable and harmful executable files from unknown or trusted sources.
11. What are the operating modes in which Database Mirroring runs? What are the differences between them?
The operating modes of Database Mirroring are as follows: Active, Active-Standby and Active-Active. The dissimilarity among them is in how data is sent to each database. In Active-Standby mode, SQL Server can’t send data from the standby server to the primary server and vice versa. In addition, database Mirroring runs in online and offline modes.
The online mode is when data replication communication can start at any point without failover or standby. In offline mode, data replication communication needs to be initiated from the master server, whereas the other secondary database needs to be brought online before it can replicate its content to the primary database.
The operating modes are high, low, and wide availability. High availability mode means the database is mirrored on both sides of the link, so if one server crashes, the data is replicated on another. Low availability provides only a read-only duplication at each node, meaning that any change made by a user will not be replicated and must be saved to the primary drive of that account – although this could prove handy in an emergency.
Widescale allows several copies of each record to be held but with different access times to each data replica, meaning users can only access the most recent information. There are three operating modes: Active-Active, Active-Standby, and Always On. Active-Active is a mix of active and standby servers where both databases run simultaneously on the same physical server. Loads can be balanced, but the system cannot be put in maintenance mode, which would mean restoring data from backups.
The disadvantages of this deployment model are Multi-stage failover: all failures need to be addressed as a whole incident, non-disruptive recovery procedures need to be developed, no protection against single points of failure.
Database administrator interview questions can be tough to crack, but you must clear them with confidence and skill. Therefore, we have penned many essential questions with answers to make it simple. We hope this article on Important Database Administrator Interview Questions is useful for the readers.