Top 50 SQL Server DBA Interview Questions and Answers 2021 UPDATED
Top 50 SQL Server DBA Interview Questions and Answers 2021 UPDATED

A View can either have all the rows of a table or specific rows based on certain conditions. Nonclustered indexes contain key values, with each key value having a pointer to the data row that contains the key value. This means that the query goes directly to the data row with a specified index; no need to go through all the data before it. These indexes are structured and stored separately from the indexed tables. You can review the most important window functions concepts with our SQL Window Functions Cheat Sheet. You can practice what you learn there on these 11 SQL window function exercises.

Instead, as the client load increases, SQL Server gradually increases its memory usage until it reaches the amount specified in the ‘min server memory’ setting. Once this threshold is reached, SQL Server will not release any memory back to the OS unless the ‘min server memory’ value is reduced. For more details, please read the SQL | Null functions article. SQL injection is a technique used to exploit user data through web page inputs by injecting SQL commands as statements. Basically, these statements can be used to manipulate the application’s web server by malicious users.

How can you create an empty table from an existing table?

This means you can use the SELECT INTO, ALTER TABLE, and TRUNCATE commands with temporary tables. You can create indexes or do anything you would do with a ‘regular’ table. Temporary tables can also be used in transactions and stored procedures, but can’t be used in the functions. Stored procedures are pre-compiled SQL statements that repeatedly perform a set of actions.

  • You can review the most important window functions concepts with our SQL Window Functions Cheat Sheet.
  • I hope you’ll have an interview experience that tries to measure your potential more than your memorization skills, but there is certainly no guarantee of that.
  • Temporary tables are automatically deleted when the connection that created them is closed.
  • You may refer to this article WHERE clause for more details on the LIKE operator.

For this, you simply need a reliable testing platform like TestGorilla. Database security is just one example of a technical skill your candidates are likely to frequently use in their work as database administrators. Other vital skills include DevOps and Git knowledge, which you can test easily with our DevOps test and Git test. The default setting for ‘min server memory’ is 0, which means that by default, SQL Server doesn’t guarantee any minimum amount of memory. However, you can set a specific value based on the server’s memory availability and the memory requirements of other applications running on the same server.

What is the difference between SQL DELETE and SQL TRUNCATE commands?

This tells SQL Server how much free space to leave in the index pages when re-indexing. Informational commands provide feedback regarding the database such as providing information about the procedure cache. Validation commands include commands that validate the database such as the ever-popular CHECKDB. Finally, miscellaneous commands are those that obviously don’t fit in the other three categories. This includes statements like DBCC HELP, which provides the syntax for a given DBCC command.

sql dba interview questions

Using this option may cause shorter run-time for DBCC CHECKDB on large databases and is recommended for frequent use on production systems. Specifying the PHYSICAL_ONLY option causes DBCC CHECKDB to skip all checks of the FILESTREAM data. Control statements form an important part of most languages since they control the execution of other sets of statements. These are found in SQL too and should be exploited for uses such as query filtering and query optimization through careful selection of tuples that match our requirements. An ‘ON DELETE CASCADE’ constraint is used in MySQL to delete the rows from the child table automatically when the rows from the parent table are deleted.

How can you prevent data loss in SQL Server?

In the left pane of the tool, I would select SQL Server Services, the right side pane displays all of the SQL Server Services/components that are installed on that machine. If the Service is displayed as (MSSQLSERVER), then it indicates it is how to become a sql dba developer a default instance, else there will be the Instance name displayed. Inside SSMS, in Object Explorer under SQL Server Agent look for Job Activity Monitor. The job activity monitor displays the current status of all the jobs on the instance.

The five general DBA interview questions and answers in this section are perfect for reviewing your applicants’ responses and finding your next database administrator. Stored Procedures are created to perform one or more DML operations on databases. It is nothing but a group of SQL statements that accepts some input in the form of parameters and performs some task and may or may not return a value. For more details please refer to our Stored procedures in the SQL article. A view also has rows and columns as they are on a real table in the database. We can create a view by selecting fields from one or more tables present in the database.

Frequently Asked SQL Server Interview Questions

A view doesn’t contain any data in itself and outputs it only when it’s run. It also saves memory, since the view result is not stored in memory. So, how do you prepare for the other parts of the interview? They could include other programming languages (e.g., Python), statistical analysis, ETL, database design, machine learning, and so on. Envisage the action plan that will have you prepared on all these fronts. And use all the available sources – such as articles, YouTube videos, courses, practice datasets, platforms with interview questions, and all kinds of different tutorials.

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