Re: Is this bad database design

mark.fergel_at_bankofamerica.com (pcmodeler) wrote in message news:<3e2d808a.0410080524.2660b07c_at_posting.google.com>...
> >
> > Mark, I had a little trouble following your description of the process.
> > by copy/alias do you multiple passes through the table do you mean
> > something like
> > "from table1 a, table1 b" where A and B are the same table and a different
> > row is grapped from each pass based on where clause conditions?
> >
> > There are a lot of applications that use parameter/value tables and the
> > effect on performance will depend on exactly how and how often then tables
> > have to be involved in queries.
> >
> > The design does not sound great but it really isn't possible to judge
> > based on the information given.
> >
> > HTH -- Mark D Powell --
> >
>
> Basically, yes, you are correct in my description. I have to make
> multiple passes through the same tables. In most cases, it's going to
> happen 4-5 times.

Sounds bad, but might not be that bad if tables are small enough and this usage pattern keeps the blocks in memory. Might abuse your cpu, though ( http://www.oreilly.com/catalog/optoraclep/chapter/ch01.pdf ).  If the tables are large and used in things like correllated subqueries, might be very bad.

jg

--
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