RE: Stupid question of the century

Can't think of any way to get around the exclusive record lock when adding a new column/field but to get around the level check we have an view/logical file unique to every application. No two RPG apps use the same file name on the "F" spec. Each RPG's unique view includes only those fields that RPG app needs and we use the input only and update tags in the logical file to control which fields each RPG can update. It is a little bit of a pain creating all the logical for each new app we write but it does pay off in the long run. We can add a new field to the physical and do not need to recompile any application immediately. And if that new field is only use by one app we only have to get the users off that one app long enough to recompile the apps logical file and the RPG app itself.

We also added a process to our nightly backup that will perform the CHGPF right after our backup is done.

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Charles Wilt
Sent: Saturday, May 09, 2009 2:34 PM
To: Midrange Systems Technical Discussion
Subject: Re: Stupid question of the century

Alan,

If you use SQL instead of RPG's RLA op-codes, you don't have to
recompile anything.

Another option, if you want to continue to use RPG's RLA, is to have
all your RPG program access through a logical file with an explicit
format, ie. define all the fields again. This way you can change the
physical without changing any logicals and thus without requiring any
recompiles. You could easily move to such a configuration simply by
renaming the current physical and creating a new logical with the name
of the old physical. (Note: I recommend using SQL DDL to define the
physicals and logicals)

Lastly, if you had a CMS, the CMS should be able to automatically
recompile anything that needs to be recompiled.

I'm pretty sure there is no RDBMS on the planet that will let you
change a file while it is in use.

Charles

On Sat, May 9, 2009 at 2:05 PM, Alan Shore <AlanShore@xxxxxxxx> wrote:

Thanks for your reply Neil
What you have described can be somewhat circumvented by using level check
of *NO (audible gasps and shouts of "heretic") and adding only alpha fields
(even if a numeric field is what is desired)
The boss's boss wants a quicker turnaround of projects, so much so that we
have been asked to look into other languages available on the AS/400 (EGL
is the first one and that might mean another thread in and of itself)
He is tired of having to wait to change/recompile  ALL the applicable
programs for a change to a file, then having to push the appropriate people
off the system so that these changes can be applied to the files on the
production system


Alan Shore
Programmer/Analyst, Distribution
E:AShore@xxxxxxxxxxx
P:(631) 200-5019
C:(631) 880-8640
"If you're going through Hell, keep going" - Winston Churchill

midrange-l-bounces@xxxxxxxxxxxx wrote on 05/09/2009 01:52:52 PM:

Let me get this straight.

I am an RPG program that has an internally described file open that the
operating system has checked has the same format level ID as the file I

was

compiled against.

And you now want to change that file so that the program will either A)

Fall

over in a heap on the next read or write operation or B) continue to

process

as normal but silently corrupt data all over the place.

I really would advise your bosses, bosses that want he wants is a bad
idea!!!!

Can we have the context of why your boss wants this? There might be a

less

risky solution.

That said I'll be shocked if anyone knows how to do want you need :-)

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Alan Shore
Sent: 09 May 2009 18:18
To: Midrange Systems Technical Discussion
Subject: Stupid question of the century

Hi guys
I've just been asked the following question by my boss's boss
Is there anyway to add new fields (columns) "on the fly" to an existing
file, without having an exclusive lock on that file.
In other words, the file is still being used while the field is added
I know that chgpf is out of the question (unless someone proves me

wrong).

I know that SQL is also out of the question (ALTER TABLE x ADD EXTRAFIELD
DEC(7, 2) NOT NULL DEFAULT 0) - again unless someone proves me wrong
If anyone knows of any way, any language, any procedure, any function to
achieve this, please drop me a line.

Thanks in advance


Alan Shore
Programmer/Analyst, Distribution
E:AShore@xxxxxxxxxxx
P:(631) 200-5019
C:(631) 880-8640
"If you're going through Hell, keep going" - Winston Churchill
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