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Posted by ZeldorBlat on 06/10/06 02:50
Erland Sommarskog wrote:
> ZeldorBlat (zeldorblat@gmail.com) writes:
> > No, it won't. If you had a list of people on a piece of paper, sorted
> > by last name and then by first name, explain how you would use that
> > list to find everyone with a first name of "Joe" without looking
> > through the entire list.
>
> Say further that with each list there is a page number to references
> where the persons appear in the book.
>
> If all you want to know is the name of the persons, you can scan
> the index, you don't have to read the whole book.
>
> It's important to keep in mind that an index can be used in two
> ways: Seek (look up data through the index tree) and Scan (read
> the entire index from left to right): While the latter is far more
> expensive, it can still be useful at times.
>
>
>
> --
> Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se
>
> Books Online for SQL Server 2005 at
> http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
> Books Online for SQL Server 2000 at
> http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx
Point taken. Thanks, Erland.
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