MS SQL Advance Interview Question with Answer - Part 2
Here are some more advanced
Microsoft SQL Server interview questions with answers:
1. What are SQL Server Views, and
why are they used?
Answer: SQL Server Views are
virtual tables that are defined by a SELECT statement and can be used to
encapsulate complex logic, simplify query writing, and provide an additional
layer of abstraction for data retrieval. Views are stored in the database and
can be used to filter, join, and transform data from one or more tables, making
it easier to retrieve specific data subsets without the need to write complex
queries repeatedly. Views can also be used to restrict access to sensitive data
by providing a controlled interface to the underlying tables, enforcing security
and data integrity rules.
2. What is SQL Server Replication,
and how does it work?
Answer: SQL Server Replication is
a feature that allows you to replicate data from one SQL Server instance to
another, either within the same server or across different servers. It is used
for maintaining data consistency, availability, and scalability in distributed
databases or for data integration between different systems. SQL Server
Replication uses a publish-subscribe model, where changes made to the published
tables are captured and stored in a replication log, and then delivered to the
subscribing servers, where the changes are applied to the corresponding tables.
Replication can be configured in various ways, such as snapshot replication,
transactional replication, and merge replication, depending on the requirements
of the data synchronization.
3. What are SQL Server Triggers, and
how are they used?
Answer: SQL Server Triggers are
special types of stored procedures that are automatically executed in response
to specific events or actions, such as inserting, updating, or deleting data in
a table. Triggers are used to enforce data integrity rules, implement business
logic, and perform automatic actions based on changes in the database. Triggers
can be written in T-SQL, CLR (Common Language Runtime) or even as server-level
triggers, and they can be used to perform actions before or after the
triggering event occurs. However, triggers should be used judiciously, as they
can introduce complexity, performance overhead, and potential for unintended
consequences if not implemented carefully.
4. What are SQL Server Constraints,
and why are they used?
Answer: SQL Server Constraints
are rules that are defined on a table to enforce data integrity and ensure that
data meets specific criteria or conditions. Constraints are used to maintain
the consistency, accuracy, and reliability of data in the database. There are
different types of constraints in SQL Server, including:
· Primary
Key Constraint: Ensures that each row in a table has a unique key value, used
to uniquely identify the row. Primary key constraints prevent duplicate key
values and are used as the primary means of identifying a row in a table.
· Foreign
Key Constraint: Establishes a relationship between two tables based on a common
key column, enforcing referential integrity. Foreign key constraints prevent
the insertion of data that violates the relationship between the tables.
· Unique
Constraint: Ensures that the values in a column or combination of columns are
unique within the table. Unique constraints prevent duplicate values in the
specified columns.
· Check
Constraint: Defines a condition that must be true for data to be inserted or
updated in a table. Check constraints validate the data against the defined
condition and prevent data that does not meet the condition from being inserted
or updated.
· Default
Constraint: Specifies a default value for a column that is used when a value is
not provided during an insert operation. Default constraints provide a default
value for a column if no value is provided explicitly.
5. What are SQL Server Transactions,
and how do they work?
Answer: SQL Server Transactions are units of work that are used to ensure the consistency, isolation, and durability of database operations. A transaction is a sequence of one or more SQL statements that are executed as a single unit, either
6. What is SQL Server Locking, and
how does it work?
Answer: SQL Server Locking is a
mechanism used to control concurrent access to shared resources in a multi-user
database environment. When multiple users or processes are trying to access and
modify the same data simultaneously, SQL Server uses locking to prevent
conflicts and maintain data integrity. Locks can be granted for different
levels of granularity, including at the row, page, or table level, and can be
of various types, such as shared locks, exclusive locks, update locks, and
more. Locks are acquired by a transaction when it starts and are released when
the transaction is committed or rolled back. Locking can impact performance and
scalability, and it is important to understand how to use and manage locks
effectively to avoid contention and optimize database performance.
7. What are SQL Server Indexes, and
why are they important?
Answer: SQL Server Indexes are
database objects that provide a fast and efficient way to look up data based on
the values in one or more columns of a table. Indexes improve query performance
by reducing the amount of data that needs to be scanned or sorted, and by
providing direct access to the relevant data pages. Indexes can be created on
one or more columns of a table, and they can be of various types, such as
clustered indexes, non-clustered indexes, and filtered indexes. Indexes are
important for optimizing query performance, speeding up data retrieval, and
improving the overall efficiency of the database. However, indexes also have
some overhead, such as increased storage space and maintenance costs, and it is
important to carefully design and manage indexes to achieve the desired
performance benefits.
8. What are SQL Server Stored
Procedures, and why are they used?
Answer: SQL Server Stored
Procedures are database objects that are used to encapsulate a series of SQL
statements into a single executable block of code. Stored Procedures are
pre-compiled, stored in the database, and can be called by name from an application
or other parts of the database. Stored Procedures are used to implement
business logic, enforce data integrity, and provide a secure and efficient way
to execute database operations. Stored Procedures can take parameters, return
values, and perform complex data manipulation or transactional processing. They
are important for improving performance, reducing code duplication, and
providing a secure and controlled way to access and modify data in a database.
9. What are SQL Server Extended
Events, and how are they used?
Answer: SQL Server Extended
Events is a lightweight and flexible event tracing framework that is used for
monitoring and troubleshooting SQL Server performance, activity, and behavior.
Extended Events allow you to capture, analyze, and interpret events that occur
within the SQL Server engine, such as query execution, resource usage, error
conditions, and more. Extended Events provide a flexible and efficient way to
collect detailed performance data, diagnose performance issues, and gain insights
into the behavior of the SQL Server instance. Extended Events can be configured
to capture specific events or conditions, and they can be used in conjunction
with other monitoring tools to gain a comprehensive understanding of the
performance and behavior of SQL Server.
These are just a few examples of
advanced Microsoft SQL Server interview questions. It is always recommended to
thoroughly study and prepare for the specific requirements and expectations of
the job and company you are interviewing with, and to be familiar with the
latest features and best practices of SQL Server. Good luck with your
interview!
10. What is the difference between a
clustered and a non-clustered index in SQL Server?
Answer: In SQL Server, a
clustered index determines the physical order of data in a table, whereas a
non-clustered index does not affect the physical order of data. A table can
have only one clustered index, which determines the physical arrangement of data
on disk, while multiple non-clustered indexes can be created on a table.
Clustered indexes are typically used on columns that are frequently used in
range-based queries or for retrieving data in a particular order, while
non-clustered indexes are used for providing fast access to specific columns or
combinations of columns.
MS SQL Advance Interview Question with Answer - Part 1
Post a Comment