John,

Glad it was helpful. There's obviously no substitute for practical experience, and mine is nil in the area.

I'd opt for a specialist too for a wrist fracture, because my wrist is critical to me and I want someone who knows to handle the 'little things' that can make a huge difference in later usage. Same for a SQL database that was very important.

You mention a specific table where a clustered index proved detrimental. I take it that the performance difference wasn't dramatic but since the area of specific benefit wasn't applicable (query performance) you elected for the performance where it mattered most. Makes good sense to me.
I do have one question though, just to round off my limited knowledge. . . was this with SQL Server 7.0 or 2000, or was it with an older release of SQL Server?
It was a while back when I read the book attentively, and I seem to remember that they had paid particular attention to clustered index improvements in 7.0.

Cheers,
Jim

>Jim
>
>Thanks for the words, that's really helpful.
>
>We get specialist SQL help when we implement databases. It saves so much angst. We can't all be experts on everything. I guess that's like a family physician calling in an orthopaedic surgeon to fix a wrist fracture. The family physician can almost certainly fix it... but why?
>
>FWIW, we have some tables without clustered indexes. These are tables whose massive insert load is intended for the rare event of access audit... perhaps once a month. The table gets insert hammered hard. Expert advice included "real life" testing on the aging server with real loads. From memory the difference with and without clustered index was measurable- worse with the clustered index.
>
>My habit is to use a clustered index in SQL Server, for reasons such as those you cite. That I do it does not make it correct... the issue you raise about index on deleted() is illustrative of how one can "know" something is true because "everyone knows" it is true. I'm glad people are brave enough to question, examples where people do not use clustered indexes are very helpful for me.
>
>Regards
>
>JR