What is an index and types of indexes. How many number of
indexes can be used per table ?

Answer Posted / jeevan

Index is nothing but an identification of each row. It will be used for quick search.

Types Of Index:
---------------

Clustered Index:
Clustered index is a physical sorting of database table’s rows in a storage media. For this reason, each table may have one clustered index. If a primary key constraint is created for a table but no clustered index exists for a table, then SQL server automatically create a clustered index on a primary key.

Non Clustered Index:
Non clustered index are created outside of the table and contain a sorted list of references to a table itself. Maximum we can use 249 clustered indexes per table.

Note:
Only 1 clustered Index can be used per table.
Maximum 249 non clustered index can be used per table.

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