"Darren New" <dne### [at] sanrrcom> wrote in message
news:4891d67e$1@news.povray.org...
> Gail Shaw wrote:
> > It's called the clustered index.
>
> I'd been told a clustered index is one in which the rows in the table
> date are in physically the same order as the rows in the index. And that
> that's why you can only have one clustered index for a table.

Mostly correct.

The clustered index is the table. The leaf levels of the cluster are the
actual data pages and they are stored physically in the order of the
clustering key. The index's b-tree is built above those pages.
A scan of the clustered index is a scan of the data pages of the table.

With a clustered index, the clustering key is the row's 'address' and is
used in all other indexes to indicate the row's location if a lookup is
necessary (to retrieve additional columns)

There's a fairly decent diagram here - :
http://msdn.microsoft.com/en-us/library/ms177443.aspx

Does thet help at all, or have I just muddied the water more?

Bear in mind, I'm talking specifically for MS SQL Server. If other database
products have something with the same name, the physical implementation may
be different

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