MS SQL Interview Questions And Answers

Introduction

MS SQL interview questions and answers are specially curated just for you. This blog in general addresses questions like MS SQL interview questions and MS SQL Server interview questions as well. MS SQL is one of the top and most active players in the world of relational database management systems (RDBMS) and in the world of computing and technology in general. IT graduates and job seekers can go through this blog to get a clear understanding of the most frequently asked interview questions and answers in MS SQL. You can visit SLAJobs to find out more about all the courses and training we offer. 

MS SQL interview questions and answers

1. What is the use of NOLOCK hint in MS SQL?

The NOLOCK hint in MS SQL Server allows a SELECT statement to read data from a table without waiting for other transactions to finish. It’s like a shortcut for quicker access.

2. Elaborate on the functions of NOLOCK hint in MS SQL.

Key points about the functions of NOLOCK:

• Dirty Read: NOLOCK lets a query see changes made by other transactions, even if they haven’t been finalized. This might mean reading data that could be changed or canceled later.
• Performance Boost: Using NOLOCK can speed up queries because they don’t have to wait for other transactions to release locks. But there’s a trade-off: the data you read might be in the middle of being changed.
• Avoiding Blocks: When multiple transactions are working with the same data, NOLOCK can prevent one transaction from getting stuck behind another. However, it might mean reading data that’s being changed by another transaction.

3. What is a schema in MS SQL?

One of the most important MS SQL Server interview questions.

In MS SQL Server, a schema is a container or namespace that is used to organize database objects, such as tables, views, procedures, and functions. It provides a way to group related database objects together and differentiate them from objects in other schemas.

4. What are aliases in MS SQL?

• In MS SQL, an alias is a temporary name assigned to a table or column in a SQL query. It allows the user to rename a table or column for the duration of the query, making the output more readable, or providing a short-term reference.
• Aliases aren’t just confined to just SELECT statements; users can use them in different parts of a query, like JOIN conditions or WHERE clauses. They offer a means to enhance the clarity and manageability of SQL queries.

5. What are entities in MS SQL?

This is one of MS SQL interview questions.

Entities are objects or items that are represented and recorded in a table in a database. When it comes to relational databases, entities are more closely related to tables in particular. Within a table, every row represents an occurrence of an entity, and each column represents a characteristic or feature of that entity. 

6. What are relationships in MS SQL?

Relationships in MS SQL represent the association or connection between tables in a relational database. These connections or relationships are usually established through primary and foreign keys, which signifies a relationship between those corresponding tables.

7. What are set operators in MS SQL?

This is one of MS SQL Server interview questions

The result set of two or more SELECT queries is usually combined using a set operator. These operators perform functions like set operations, such as union, intersection, and difference, on the results of multiple queries. 

8.  What are some of the commonly used set operators in MS SQL Server?

This is one of the most important MS SQL Server interview questions. The following describes the commonly used set operators in MS SQL Server:

• UNION: The UNION operator combines outcomes from two or more SELECT statements without including duplicate rows.
• UNION ALL: The UNION ALL operator combines outcomes from two or more SELECT statements, including duplicate rows.
• INTERSECT: The INTERSECT operator retrieves common rows appearing in the results of two SELECT statements.
• EXCEPT or MINUS: The EXCEPT (or MINUS) operator fetches rows in the first SELECT statement that are absent in the second.

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9. What are hotfixes in MS SQL?

One of the important MS SQL Server interview questions.

Hotfixes are software updates that are specially deployed by Microsoft to deal with bugs or issues with SQL Server. Hotfixes are primarily created to solve problems that are detected by Microsoft or reported by users.

10. What are some salient features of hotfixes in MS SQL?

This is one of the most important questions in MS SQL interview questions. Features of hotfixes are listed below:

• Specific issue resolutions: Hotfixes are introduced to tackle particular problems, bugs, or vulnerabilities that are identified within a specific version of SQL Server. Unlike comprehensive updates such as service packs, hotfixes are tailored to address precise issues.
• Limited Circulation: Hotfixes typically have a more restricted distribution compared to service packs. They are provided to customers who explicitly request a resolution for a specific issue, typically by reaching out to Microsoft Support.
• Thorough Testing: Hotfixes undergo testing to confirm their effectiveness in resolving the identified issue without introducing new complications. However, due to their targeted nature, hotfixes may not undergo the same extensive testing as service packs.
• Cumulative Updates: Microsoft frequently releases cumulative updates, bundling together multiple hotfixes and enhancements. Cumulative updates serve as a consolidated package of individual hotfixes, undergoing testing as a unified update.
• Significance of Regular Updates: Ensuring SQL Server is regularly updated with the latest hotfixes and cumulative updates is crucial for preserving system stability, security, and performance. Consistent application of updates is essential to addressing known issues and leveraging performance improvements and security enhancements.

11. How are patches different from hotfixes?

This is one of the important MS SQL Server interview questions and answers. 

12. What is a view in MS SQL?

A view acts as a virtual table created from the outcome of a SELECT query. Unlike physical tables, it doesn’t store the data directly but offers a means to showcase the query result in a tabular format. Views are beneficial for streamlining intricate queries and managing access to particular columns within the database.

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13. What are intent locks in MS SQL?

• Intent locks in Microsoft SQL Server function as a signaling mechanism for a transaction to express its intention of obtaining a specific type of lock on a resource, like a table or page. The primary purpose of these locks is to manage the interactions between concurrent transactions and mitigate potential conflicts that may arise from different lock types.
• These locks are integrated into a hierarchy of lock modes and are applicable across multiple levels, encompassing tables, pages, and rows. They play a pivotal role in orchestrating how transactions interact in a multi-user environment, facilitating conflict prevention and control over transaction behavior.

14. Explain the main types of intent locks.

There are two primary categories of intent locks:

• Intent Shared (IS) Locks:

An intent shared lock signifies a transaction’s intention to secure a shared lock on a lower-level resource, such as a row, within a higher-level resource, like a page or table. This conveys the intent to read data without any plans for modification.

• Intent Exclusive (IX) Locks:

An intent-exclusive lock communicates a transaction’s intention to obtain an exclusive lock on a lower-level resource within a higher-level resource. This explicitly indicates the intent to modify data and prevents other transactions from acquiring conflicting locks.

15. What are the objectives of intent locks in MS SQL?

The objectives of intent locks encompass:

• Concurrent Transaction Management:

Intent locks aid in overseeing concurrent transactions by indicating a transaction’s plan to acquire locks on lower-level resources. This proactive signaling helps prevent conflicts between transactions with diverse intentions for the same resources.

• Avoidance of Deadlocks:

Intent locks play a role in preventing deadlocks by conveying information about a transaction’s intentions. When a transaction secures an intent lock, it communicates its anticipated actions to other transactions, enabling them to make informed decisions regarding their lock acquisitions.

• Management of Hierarchies:

Intent locks are integral to a hierarchical structure that includes shared (S) locks, exclusive (X) locks, and other lock types. This hierarchy facilitates effective management and escalation of locks in SQL Server based on the stated intentions of the transactions.

• Optimization of Performance: 

Performance optimization is achieved through intent locks by offering a broad perspective on a transaction’s intentions. This overview reduces contention for resources, contributing to an overall enhancement in the efficiency of the locking system.

16. What is SQL Server Profiler in MS SQL?

SQL Server Profiler is a software tool offered by Microsoft SQL Server, enabling database administrators and developers to capture and scrutinize events happening within a SQL Server instance. Equipped with a graphical user interface, it serves as a valuable resource for monitoring and analyzing activities in SQL Server, proving instrumental for tasks such as performance tuning, troubleshooting, and auditing.

17. What are the key features of SQL Server Profiler in MS SQL?

Key functionalities and characteristics of SQL Server Profiler comprise:

• Event Capture:

SQL Server Profiler records a diverse array of events, encompassing SQL statements, stored procedure calls, login/logout events, and more. Users have the flexibility to choose particular events of interest for monitoring.

• Trace Templates:

Profiler presents preconfigured trace templates that streamline the task of capturing standard sets of events. These templates cater to various objectives, such as performance tuning, troubleshooting, and auditing.

• Customizable Traces:

Users possess the capability to craft personalized traces by specifying events, data columns, and filters based on their monitoring prerequisites. This customization option allows for precise adjustments to the profiling process.

• Real-time Monitoring:

Profiler facilitates real-time monitoring, empowering users to observe and analyze events as they transpire. This proves especially advantageous for promptly identifying performance bottlenecks and addressing issues in real-time.

18. What are SQL Server instances in MS SQL?

Within Microsoft SQL Server, an instance denotes an active installation of the SQL Server software. Each instance functions autonomously on a server, enabling the coexistence of multiple instances on a single physical or virtual machine. Distinguished by a unique name, each instance possesses its own distinct databases, security configurations, and settings.

Conclusion: 

MS SQL interview questions and answers are guaranteed to provide you with confidence and support in your interviews. MS SQL has the added strength of Microsoft and SQL, which will make database management easy and more widely used for organizations across the world. So a career in MS SQL has a great scope compared to other technological organizations around the world. This blog features questions specific to MS SQL interview questions and answers to MS SQL Server interview questions as well. Being one of the biggest players in the RDMS field and in the field of technology through Microsoft, MS SQL is the ideal and first choice for most IT graduates and job seekers in the world, which makes this job one of the most in-demand jobs in the world. So go through this blog and give yourself a massive advantage over other candidates. Best wishes for your career, and I hope you succeed in your respective interview and contribute greatly to the world of technology.