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

If you do it correctly, that means you end up with logicals with exactly
the same format as the ones you currently have, they should have the same
format level identifier. The only thing that could throw a monkey wrench
into that is if you compile them in a different order and the wrong one
ends up owning a shared access path.

On Wed, Jul 31, 2019 at 3:48 PM Alan Shore via MIDRANGE-L <
midrange-l@xxxxxxxxxxxxxxxxxx> wrote:

Thanks for the reply Mark
Now that this idea has sunk in a little more, here is where I am having a
problem
Tell me where I am going wrong

I change the physical to add a new field (called - NEWTOKEN)
Create new logicals - defining all the fields in the physical (including
NEWTOKEN) and use these logicals where the new field NEWTOKEN is required

Here is the point I need to make
The logicals that are already built - but do NOT define ANY field - will
be recreated to include the NEWTOKEN field and will have an new level
identifier - correct?

That means the programs that use these logicals will still need to be
recompiled
OR
Change the level check on these logicals to *NO

Im not saying that this is a showstopper for this process - just trying to
cover all bases BEFORE work is started where I end up saying -
HMMMMMMMMMMMMMMMM

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 Mark Waterbury
Sent: Wednesday, July 31, 2019 3:38 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

Alan, and Charles,

Do not force the issue of converting from DDS to SQL DDL ... at least, not
"right away" ...

In this case, for "legacy" applications, you can still use DDS to create a
Logical File that has the exact same record layout, record format level ID,
and it will have an index and so "native" Record I/O (e.g. RPG SETLL, READE
etc.) will all work just fine.

This technique has been available since the days of the System/38 and CPF,
and I am very surprised that more people are seemingly not aware of this
method to avoid having to recompile all of the programs that use the "base"
physical file, every time you want to add or change a single field or
column in a database physical file.

Hope that helps,

Mark S. Waterbury

On Wednesday, July 31, 2019, 3:07:22 PM EDT, Charles Wilt <
charles.wilt@xxxxxxxxx> wrote:

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

On Wed, Jul 31, 2019 at 12:19 PM Alan Shore via MIDRANGE-L <
midrange-l@xxxxxxxxxxxxxxxxxx> wrote:

Thanks Sam
That article definitely helped
However, Im still not 100% sure this will help in what I need

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 Sam_L
Sent: Wednesday, July 31, 2019 2:08 PM
To: midrange-l@xxxxxxxxxxxxxxxxxx
Subject: Re: [EXTERNAL] Re: Expanding a field in a file or adding a
new field to the file

This article *might* help understand what Charles is suggesting:

https://www.mcpressonline.com/programming/rpg/use-a-logical-file-layer
-to-minimize-recompiles-from-field-additions

Sam

On 7/31/2019 2:00 PM, Alan Shore via MIDRANGE-L wrote:

Hi Charles
Im not too sure I have an understanding on this

I tried to create some type of diagram, following what you suggested
- but its NOT working out Any chance you could make it simpler for a

simpleton like me?

Alan Shore

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