Luis Cazares - Thursday, August 3, 2017 9:45 AM

itmasterw 60042 - Thursday, August 3, 2017 9:23 AM

Hi,

I have been looking all over the net and in books to findwhen to use a clustered and/or non-clustered index; and all I get isdefinitions, not when to use one or both. Can you please tell me how I canlearn this, or would you be able to give me some general steps to do this?

Thank you

Clustered indexes should be used always. You can read some recommendations about it in here: http://www.scarydba.com/2011/04/04/sql-universityrecommendations-for-a-clustered-index/ . (Be sure to read the links in the conclusion)
Be careful when designing them as they're the base for performance tuning and other features.
Non-clustered indexes are used as an additional performance enhancement to retrieve data (or validate constraints). In my opinion, you should never have a non-clustered index without a clustered index. If you understand how each index works, you'll find it easier to understand when to use them.