Top 30 SQL Server DBA Interview Questions and Answers

DROP command removes a table from the database and operation cannot be rolled back. Online Transaction Processing (OLTP) manages transaction based applications which can be used for data entry, data retrieval and data processing. Unlike OLAP systems goal of OLTP systems is serving real-time transactions. User defined functions are the functions written to use that logic whenever required.

During his tenure at SentryOne, Jason has served as senior software developer and founded both Client Services and Product Management. His diverse background with relevant technologies made him the perfect choice to build out both of these functions. Remember that interviews are two-way affairs, and you should be interviewing them as much as they are interviewing you. Make sure to have your server DBA interview questions ready when you’re given the opportunity to ask them. Complete research on the company and role to make sure it’s what you want. If it is, complete more research to demonstrate your high level of interest.

Q. Explain Replication in SQL Server.

Scalar User-Defined Function A Scalar user-defined function returns one of the scalar data types. These are the type of user-defined functions that most developers are used to in other programming languages. You pass in 0 to many parameters and you get a return value. What I’ve covered here is nowhere close to the full scope of what you might encounter. But based on my experiences both as a job candidate and as a hiring manager, I hope it helps in some small way.

• SubQuery is always executed first, and the result of subquery is passed on to the main query.
• We will use a system stored procedure sp_change_log_shipping_secondary_database to make this change.
• For example- max(),count() are calculated with respect to numeric.
• This means, it returns all the rows from the left hand side table and all the rows from the right hand side table.
• Hotfixes are commonly developed and used by developers to rectify SQL database problems that may arise from time to time.
• Finally, miscellaneous commands are those that obviously don’t fit in the other three categories.
• In SQL a Subquery can be simply defined as a query within another query.

For more details please read the Difference between Commit and Rollback in SQL article. The SQL BETWEEN condition allows you to easily test if an expression is within a range of values (inclusive). It can be used in a SELECT, how to become a sql dba developer INSERT, UPDATE, or DELETE statement. The SQL BETWEEN Condition will return the records where the expression is within the range of value1 and value2. For more details please read the SQL | AND and OR operators article.

Why SQL server is better than other databases?

Does your next database administrator have the right expertise to become a member of your team? The database engine uses intent locks to protect placing a shared (S) lock or an exclusive (X) lock on a resource (lower in the lock hierarchy). Intent locks are named thus because they are acquired before a lock at the lower level and therefore signal the intent to place the locks at a lower level. The READ_COMMITTED_SNAPSHOT option for the READ_COMMITTED optimistic model and the ALLOW_SNAPSHOT_ISOLATION option for the SNAPSHOT isolation level. Within the REPEATABLE_READ and SERIALIZABLE isolation levels, locks are held/retained for the duration of the transaction, unlike within the READ_COMMITTED isolation level. SQL Server 2005 databases are compatible with SQL Server 2008.

These are all single-row functions i.e. provide one result per row. An SQL query is used to retrieve the required data from the database. However, there may be multiple SQL queries that yield the same results but with different levels of efficiency. An inefficient query can drain the database resources, reduce https://remotemode.net/ the database speed or result in a loss of service for other users. So it is very important to optimize the query to obtain the best database performance. A Database is defined as a structured form of data storage in a computer or a collection of data in an organized manner and can be accessed in various ways.

Q3. What do you mean by DBMS? What are its different types?

The expressions are evaluated in the order that they are supplied, and the function’s result is the first non-null value. Only if all of the inputs are null does the COALESCE method return NULL. Non-Clustered Index does not alter the physical order of the table and maintains a logical order of the data. This index reorders the physical order of the table and searches based on the basis of key values. Relational databases are SQL, while non-relational databases are NoSQL. At least one set of WHEN and THEN commands makes up the SQL Server CASE Statement.