• Subject: Re: PF File Definition questions...
  • From: Rob Berendt <rob@xxxxxxxxx>
  • Date: Fri, 15 Oct 1999 8:59:35 -0500

Most of our package PF's do not have a key.  Any new ones I create, 
do.  I am trying to follow database rules.  You cannot do Referential 
Integrity on files without a primary key.  Also, I avoid multiple 
members for the same reason.  I've had to use trigger programs when 
simple RI would have been effective just because of the multiple member 
situation.  We have a UPS.  We use RAID.  The risk mentioned by one
person aren't overweighing the benefits.  At least in our situation.





clewis@iquest.net on 10/14/99 09:31:17 PM
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Subject:        PF File Definition questions...

Hi Folks !

Was wondering how folks define PF's when it comes to keyed or not.

Is there something I'm missing when it comes to NOT having the "most
common" field(s) in a PF defined in the PF a key field(s) ?

Then handle the less obvious stuff in LF's ?

One less access path...

Why PF's with NO key fields ?

Also, I was told YEARS ago (on the S/38) that you should try to keep the
number of LF's over a PF to a minimum, say 3, 4 tops and let your
program handle the level breaks, etc. to help system performance. Even
on the AS/400 there has GOT to be some truth to that just due to the
fact that there aren't a BUNCH of access paths that have to be rebuilt.
I've seen some vendor packages with a hundred LF's over one PF !!!!

Thanks !

Chuck

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