RE: MVC in RPG?

3. If you still have to do research on all programs that uses the DB
layer when changing attribute of a field, you are really not gain much
from it. As far as adding new field, it is only true if your DB layer
does not have procedure that allowed caller to get the entire DS of the
file. Unfortunately, getting the entire DS is a pretty useful function
to have.


4. There are several ways to go around the problem, the point being
that are you really gaining anything from DB layer? Why replace RPG io
functions that all RPG developers are familiar with with your own io
functions that no new comer can understand without additional trainings?




-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Wilt, Charles
Sent: Tuesday, October 02, 2007 2:10 PM
To: RPG programming on the AS400 / iSeries
Subject: RE: MVC in RPG?


3. Changing field sizes/attributes will always be trouble. However,
with a DB layer you could get away with for instance expanding a name
field from 30 to 50 without a mass compile assuming that you decide
there's only a few place where you need the full name. More useful is
the ability to add fields without a mass recompile.

4. Activation groups play a big role in handling this. You could also
design in some ways to handle this.

I'm a fan of the DB layer. In fact, I'm partial to having a DB layer +
a business logic layer.


Charles

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Lim Hock-Chai
Sent: Tuesday, October 02, 2007 12:50 PM
To: RPG programming on the AS400 / iSeries
Subject: RE: MVC in RPG?

I agree that some form of export procedures should be provided to
access the master files that you described in your email. However,
that is likely to be an exception to all files in your system.
Exception, IMHO, should not become the norm on how one handles access
to all files in the system.

3. OK. I just want to point out what Rob D (I think Rob said this
before. Sorry if I miss quote) has mentioned before: It is a myth for

developer to think that DB layer will prevent mass recompile when
field change is required.

4. Your DB layer basically has the same effect of opening all files
with share data path of *yes. The could be come problematic nor
matter how well you design your system.

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