when and what to use index

Hi everyone,

When and what type of data do we need to use clustered and non-clustered index?

Thanks,

V1rt

What type: Any data type where the data in the column is highly selective (different in each row, or nearly so) and the type is not Text or Image or Binary.

When: it helps to speed up the queries you need to run.

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Yes, I am a geek. I know. I can't help it.

I'm sorry, my question was wrong. What I really mean is, when do we need to create a non-clustered or a clustered index? For example, if I'm looking for a specific string, should I use non-clustered?

Thanks!

Each table can have only one clustered index, which determines the order in which the data is actually stored. You should select a column for the clustered index where that ordering is helpful, for example in joins or in selection of ranges (value between X and Y). Any other indexes have to be non-clustered. Does that help?

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Yes, I am a geek. I know. I can't help it.

It's is hard to give you all possible hints in a few sentences, this is really topic one can write a few articles about. <br />I am sure there are few good articles about that on this site and elswhere. <br />Read them and also follow discussion here, after a month or two you may even become the expert in that area <img src='/community/emoticons/emotion-1.gif' alt='' />

Thanks guys! You guys are so helpful!!! <img src='/community/emoticons/emotion-1.gif' alt='' />