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Posted by Tony Rogerson on 07/17/06 09:15
Slight variation:
Data is clustered WITH the index, basically the index leaf level is the
actual data whereas on non-clustered indexes the leaf level of the index is
a copy of the data (just the key columns) and a bookmark (if table is a heap
then a pointer otherwise its a copy of the clustering key).
Tony.
--
Tony Rogerson
SQL Server MVP
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<anonieko@hotmail.com> wrote in message
news:1153120535.287054.238660@75g2000cwc.googlegroups.com...
>A lot of detailed discussion explains the difference between clustered
> and non-clustered indexes. But very few 'clarifies' why the term used
> is 'clustered'. Well, once and for all, this is my take.
>
> *** The 'CLUSTERED' adjective refers to the INDEX being clustered (set
> adjacent) to the DATA.
>
> This means if you found the index, the data is already there beside it
> (you don't have to look anywhere else). From this note, everything
> hopefully becomes clearer to you. (You can now read further in the tech
> book :-).
>
>
> So, the next time you are asked to explain what is a clustered (or
> non-clustered ) index think of the above.
>
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