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Saturday, 27 January 2024

20 Basic questions on MS SQL database.

 1. Question: What is Microsoft SQL Server (MS SQL)?

   - Answer: Microsoft SQL Server is a relational database management system developed by Microsoft. It is widely used for storing, retrieving, and managing data.

 

2. Question: Explain the difference between a clustered and a non-clustered index in MS SQL Server.

   - Answer: A clustered index determines the physical order of data rows in a table and is used for sorting and searching. A non-clustered index, on the other hand, creates a separate structure for indexing without affecting the physical order of data.

 

3. Question: What is the purpose of the T-SQL language in MS SQL Server?

   - Answer: Transact-SQL (T-SQL) is a set of programming extensions to SQL used in MS SQL Server. It includes additional features like procedural programming, local variables, and error handling.

 

4. Question: How can you optimize a query in MS SQL Server?

   - Answer: Query optimization involves creating appropriate indexes, avoiding unnecessary joins, using proper data types, and optimizing complex queries. Execution plans and statistics can be analyzed to identify performance bottlenecks.

 

5. Question: What is the role of the SQL Server Agent in MS SQL Server?

   - Answer: SQL Server Agent is a component in MS SQL Server that automates tasks, schedules jobs, and manages alerts. It is used for tasks like database backups, data integrity checks, and running scheduled jobs.

 

6. Question: Explain the concept of a stored procedure in MS SQL Server.

   - Answer: A stored procedure is a precompiled collection of one or more SQL statements stored in the database. It can accept parameters, return values, and be executed using a single call, improving performance and code reusability.

 

7. Question: How does MS SQL Server handle transactions, and what is the purpose of the `BEGIN TRANSACTION` statement?

   - Answer: MS SQL Server supports transactions using the `BEGIN TRANSACTION`, `COMMIT`, and `ROLLBACK` statements. The `BEGIN TRANSACTION` statement marks the beginning of a transaction, and `COMMIT` or `ROLLBACK` ends it.

 

8. Question: What is the purpose of the `sp_who` and `sp_who2` stored procedures in MS SQL Server?

   - Answer: `sp_who` and `sp_who2` are stored procedures in MS SQL Server used to display information about current user connections, sessions, and processes.

 

9. Question: Explain the concept of SQL Server Replication.

   - Answer: SQL Server Replication is a set of technologies for copying and distributing data and database objects from one database to another. It ensures data consistency across distributed systems.

 

10. Question: How can you monitor and optimize SQL Server performance using SQL Server Profiler?

    - Answer: SQL Server Profiler is a tool used to monitor and analyze SQL Server events. It captures events like query execution, stored procedure calls, and errors, helping in performance analysis and optimization.

 

11. Question: What is the purpose of the SQL Server Management Studio (SSMS)?

    - Answer: SQL Server Management Studio is a graphical tool for managing and interacting with MS SQL Server. It provides a user interface for database development, administration, and maintenance.

 

12. Question: Explain the concept of SQL Server Index Fragmentation.

    - Answer: Index fragmentation occurs when data pages in an index are not in sequential order. It can lead to decreased query performance. Fragmentation can be reduced using index maintenance operations like rebuilding or reorganizing.

 

13. Question: What are the different types of backups supported by MS SQL Server?

    - Answer: MS SQL Server supports full backups, differential backups, and transaction log backups. Full backups include all data, differential backups capture changes since the last full backup, and transaction log backups capture changes since the last log backup.

 

14. Question: What is the purpose of the `NOLOCK` hint in MS SQL Server queries?

    - Answer: The `NOLOCK` hint is used to allow a SELECT statement to read uncommitted data from another transaction. It can improve query performance but may result in reading uncommitted or "dirty" data.

 

15. Question: How does MS SQL Server handle deadlocks, and what is a deadlock graph?

    - Answer: MS SQL Server uses a deadlock detection mechanism to identify and resolve deadlocks by choosing a victim to roll back. A deadlock graph is a visual representation of the deadlock, showing the involved processes and resources.

 

16. Question: Explain the purpose of the SQL Server CHECK constraint.

    - Answer: A CHECK constraint in MS SQL Server is used to limit the values that can be placed in a column. It ensures that data in the column satisfies a specific condition.

 

17. Question: What is SQL Server AlwaysOn Availability Groups, and how does it enhance high availability?

    - Answer: SQL Server AlwaysOn Availability Groups is a high-availability and disaster recovery feature. It allows multiple databases to be grouped together and provides failover support, ensuring continuous availability.

 

18. Question: How can you secure a MS SQL Server database?

    - Answer: Securing MS SQL Server involves implementing strong authentication, configuring firewalls, encrypting data in transit and at rest, using role-based access control, and regularly applying security updates.

 

19. Question: What is the purpose of the SQL Server `MERGE` statement?

    - Answer: The `MERGE` statement in MS SQL Server is used to perform insert, update, or delete operations on a target table based on the results of a join with a source table. It streamlines the process of handling changes in a data set.

 

20. Question: How does MS SQL Server handle the "Tempdb" database, and why is it important?

    - Answer: "Tempdb" is a system database in MS SQL Server used to store temporary objects, intermediate results, and temporary tables. It is crucial for various SQL Server operations, including sorting, grouping, and joins. Proper management of "Tempdb" is important for optimal performance.

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