Posted by rod.weir on 04/04/06 09:22

Hi Tony,

Thanks for your input.

Performance problems can be tricky to sort out with nested views. For
example, I had a poorly performing query that was the product of
several "child" views. It turned out that one of the child views about
3 levels deep had a ORDER BY clause that was slowing everything down.
When I removed the order by from that view, everything sped up. It
took a while to diagnose, but it worked out OK.

Which brings me to a point here. I develop these views and work very
hard to performance tune them and give them all logical and
object-oriented names. Each view is named so that you can tell what
it's lineage is. I write these views for a commercial application and
they are not modified in any way once they are shipped. Once
everything is set up, they work great.

The biggest reason people seem to dislike embedded views is because of
the maintenance involved. Being an application vendor, this is our
responsibility and our problem. This is factored into the development
process, so it's not a real issue to me. I guess the reason for
posting this thread is to learn more about the technical reasons - ie.
SQL Server reasons why these are bad, not necessarily the human
reasons, because I can handle these.

Thanks,

Rod.

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