There are thousands of blog posts and articles online that talk about the most common interview questions for SQL DBA positions. However, even though some of them are useful, the best way for you to prepare for an SQL DBA interview is to understand everything about SQL Server databases.
This is because different organizations and hiring managers will target their questions on the kind of skills that they are looking for. This can be dictated by the models of businesses and requirements when it comes to their databases.
That notwithstanding, let us look at some of the most common interview questions for SQL DBA positions.
1. How Can You Trace the Traffic Hitting Your SQL Server?
You can use the SQL Server utility known as SQL profiler to check traffic hitting any instances on your SQL server. You can also go ahead and filter the traces if you want to check the captured transactions.
This helps in reducing the incurred overhead. You can save, search, and replay the trace files for troubleshooting purposes.
2. Why Should You Monitor Your SQL Server and How?
Proper SQL Server monitoring gives DBAs enough time to implement new solutions and processes since they are not busy with numerous daily checks and investigatory tasks. In addition, it ensures that they do not continually fight surfacing problems instead of finding the root cause of those particular problems.
There are different tools that DBAs can use for server monitoring. The most important thing is to make sure that they are using the right tools and avoid manual monitoring of their servers. An example of a tool they can use is the SolarWinds SQL Sentry.
3. Can You Explain What a Four-Part Name is?
A four-part name can be defined as the parts of an object name in SQL Server used to uniquely identify the object in an SQL environment.
The parts, from first to last, include;
- The instance.
- The database.
- The schema.
- The object name.
4. Should You Use the SQL Agent and Why?
Yes, you should use the SQL agent when scheduling jobs in an SQL Server. You can schedule jobs to ensure that they run at certain times or set intervals when certain events take place.
You can also execute jobs on demand. The SQL agent plays a vital role when scheduling administrative tasks like backups.
5. What is a Linked Server and How Can You Use it?
A linked server can be defined as a reference between two or more SQL servers. You can use it when creating a link server on your SQL Server. For instance, you might find yourself in a situation where you have data on another SQL Server that you need to use for your system. Through a link server, you can create a connection that allows you to use that data.
6. How Do You Control Free Space in Your Index Pages?
You start by setting a fill factor for your indexes. This will allow the SQL Server to know the amount of space that it needs to leave in your index pages. With this, you will easily achieve fewer splits among your pages.
7. Do You Know Any DBCC Commands and What They Do?
Some of the most commonly used DBCC commands include;
- DBCC CHECKDB: This command checks for integrity issues and page allocation in the database.
- DBCC CACHESTATS: This command will provide information about all the objects that are in the buffer cache in real-time.
- DBCC DBREINDEX: This command is used when re-indexing your tables. You need to check the indexname and fillfactor when using this command.
- DBCC CHECKTABLE: This checks to find out the allocation of pages within an index or table. It also checks for integrity issues.
8. Tell Us About the Authentication Modes Supported by SQL Server.
The authentication modes supported by SQL Server include;
- SQL Server Authentication.
- Windows Authentication.
- Mixed-Mode Authentication.
You can use mixed-mode authentication when you want to use the other two authentication modes to access your SQL Server.
9. What Are Candidate, Alternate, and Composite Keys?
A candidate key is a key used to uniquely identify each of the rows in a table. It can also be defined as the primary key in a table. In case a table has multiple candidate keys, one of them becomes the primary key while the others are known as alternate keys. If you combine more than one key, you form a composite key.
10. What Does ACID Stand for?
A – Atomicity, C – Consistency, I – Isolation, and D – Durability. It is a fundamental concept behind database administration and design.
These are some of the most common interview questions for a SQL DBA position. You can also gain more knowledge with some of the best SQL tutorials online. With these answers, and of course more research, you can be sure of acing the interview.
