Posted by Erland Sommarskog on 04/05/06 00:33

Danny (djscroggins@verizon.net) writes:
> 2. Avoid transformations in the views. Performance can really suffer by
> using things like Case statements. You may think.. Just this one report
> will use this view and it doesn't need to be fast. However, a year from
> now I promise someone will see the name of the view and what it returns
> and pile more code on top of it.

Yes, that's one thing that make me nervous about views. Some thinks a
view has a column he needs that, and then he builds a new on that. Problem
is that when you expand the entire view, some underlying big table may
appear several times in view, being in fact joined to itself on the primary
key.

In our shop, we were for a long time without views at all. One project
added views into one corner of the database, where I think it actuall
made sense. (I was not involved myself.) I actually added two views to
the application for our latest version. These views are quite convoluted
and probably not very effective. But these views are there only for
compatibility. That is, I reworked some piece of data is stored, but
there were too many procedures to change right now, so these views
mimick the old tables

--
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

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