Having lots of RPG apps using the same LF file and having all fields in every LF makes a change to the physical file a real pain in the butt. You need to recompile every RPG app even if they are not affected by the change. (and depending on your auditors they might want to have documentation as to why each of those apps were recompiled) We have 100 LFs built over the same PF each with the same key field list. There is only one access path shared by all 100 LFs and each LF only uses the fields the app needs. In essence each application has its own view of the database much like an SQL select that list only the fields the application needs.
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Tommy.Holden@xxxxxxxxxxxxxxxxxxxxx
Sent: Thursday, March 13, 2008 9:18 AM
To: Midrange Systems Technical Discussion
Subject: RE: Are we insane? Unique use of native DB2
i hear a lot of "using the same keys" talk....why not just have a single
LF with those keys? if you need more fields in the key list then do some
due diligence BEFORE creating the LF and make the full key then use
partial key lists in the RPG programs. i shudder when i see 5+ LFs with
the same 2 key fields over and over (yes you might need additional LFs for
change of "sub" key fields...)but really why add unnecessary complexity??
Thanks,
Tommy Holden
From:
Mike Cunningham <mcunning@xxxxxxx>
To:
"'Midrange Systems Technical Discussion'" <midrange-l@xxxxxxxxxxxx>
Date:
03/13/2008 07:58 AM
Subject:
RE: Are we insane? Unique use of native DB2
Many LFs each with an access path attached is bad and you are right,
before the days of the system automatically sharing an access path you
could kill a system real easy doing what we are doing but shared access
path has taken care of that.
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [
mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Thursday, March 13, 2008 8:14 AM
To: Midrange Systems Technical Discussion
Subject: Re: Are we insane? Unique use of native DB2
I did see a vendor application where they accessed only by the logicals.
The original LF may have had all fields. As the file got Y2K'd the
original LF only held the same fields as it used to. Granted, the dates
were shrunk back down to 6 characters or numbers so that existing programs
that touched this didn't need to be recompiled. If you wanted the full
dates, etc, you used one of the newer logical files.
However, they didn't use a separate LF on each program. I can still
remember John Sears lectures on the evil of too many LF's. Then I
remember an artical in iSeries 400 Experts Journal by Skip M that most of
the overhead of all those LF's was pretty much done away with several
releases ago.
Rob Berendt
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