What is a Linked Server?

Linked Servers is a concept in SQL Server by which we can add other SQL Server to a Group and query both the SQL Server databases using T-SQL Statements. With a linked server, you can create very clean, easy to follow, SQL statements that allow remote data to be retrieved, joined and combined with local data. Storped Procedure sp_addlinkedserver, sp_addlinkedsrvlogin will be used add new Linked Server.

What is the use of DBCC commands?

DBCC stands for database consistency checker. We use these commands to check the consistency of the databases, i.e., maintenance, validation task and status checks.
E.g.
DBCC CHECKDB - Ensures that tables in the db and the indexes are correctly linked.DBCC CHECKALLOC - To check that all pages in a db are correctly allocated.DBCC CHECKFILEGROUP - Checks all tables file group for any damage.

What is cursors?

Cursor is a database object used by applications to manipulate data in a set on a row-by-row basis,instead of the typical SQL commands that operate on all the rows in the set at one time.
In order to work with a cursor we need to perform some steps in the following order:

• Declare cursor
• Open cursor
• Fetch row from the cursor
• Process fetched row
• Close cursor
• Deallocate cursor

What are the different index configurations a table can have?

A table can have one of the following index Configurations:

1. No indexes
2. A clustered index
3. A clustered index and many nonclustered indexes
4. A nonclustered index
5. Many nonclustered indexes

What is the difference between clustered and a non-clustered index?

A clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table can have only one clustered index. The leaf nodes of a clustered index contain the data pages.

A nonclustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows on disk. The leaf node of a nonclustered index does not consist of the data pages. Instead, the leaf nodes contain index rows