Re: [EXTERNAL] Re: Expanding a field in a file or adding a new field to the file

Alan,

Here is a good article that explains the technique of using DDS PFs and LFs -- e.g. rename the original PF, then create a new LF with the same name as the original PF ... to avoid having to recompile most programs due to "level checks."
https://www.mcpressonline.com/programming/rpg/use-a-logical-file-layer-to-minimize-recompiles-from-field-additions


As I mentioned in a prior reply, this technique has been available since System/38 CPF days.  :D

I hope that helps,

Mark S. Waterbury

On Wednesday, July 31, 2019, 3:29:45 PM EDT, Alan Shore via MIDRANGE-L <midrange-l@xxxxxxxxxxxxxxxxxx> wrote:

Thanks for your reply Charles
I have been re-reading your prior e-mail from before AND the article
Trying to get it through my thick skin is no easy achievement

I am now JUST beginning to see the light

So this would be the third option

3.      Adding a new field (at the end of all the files) - but create new logicals that would specify this new field and change the programs to use the new logicals

Alan Shore
E-mail : ASHORE@xxxxxxxx
Phone [O] : (631) 200-5019
Phone [C] : (631) 880-8640
'If you're going through hell, keep going.'
Winston Churchill


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxxxxxxxx] On Behalf Of Charles Wilt
Sent: Wednesday, July 31, 2019 3:07 PM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: Re: [EXTERNAL] Re: Expanding a field in a file or adding a new field to the file

Sure it will...

Assume you have 100 programs that access the table now.
But only 10 actually do anything with the CC token column...

Instead of recompiling and testing 100 programs, you need only recompile and test 10.

Only catch is RPG programs that use RPG record level I/O through an SQL index (instead of a keyed logical file) Those would also need to be recompiled and tested as explicitly including columns in an SQL index changes the record layout...but that would only be needed this time.  (Time time you change the table, you're golden.)  I thought I had an RFE to change this...but guess not..

Charles