SQL Server Index

Some Times we want to retrive data fastly without wasting time to retrive it. SQL Server Indexes can greatly help to make data retrival fast and provide quick access to tables.

Therer are four type of indexes in SQL Server 2000/2005.

1) Unique Key Index

2) Clustered Index

3) Non Clustered Index

4) Compsite Key Index

Unique Key Index:

As the name suggest this index does not allow duplicate values in rows. So it checks whether the data is unique or it Other wise it will give a error.

Clustered Index:

Clustered Index dictates the physical storage order of the data in the table. A table can have only one clustered index.

Non Clustered Index:

A non clustered index is a seperate index structure indepedent of the physical storage order of data. Sql Server 2000 alllowed 249 indexes per table.

Compsite Key Index:

As the name suggest in the composite key index two or more columns of tables to make a single unit. Sql Server 2000 allow 16 indexes per table.