RE: MVC in RPG?

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: Joel Cochran
>
> In RPGBeans, the database is read one time and the values are stored in
> the ServiceProgram, so no you are not chaining each time.

I'm not going to get into the debate about whether database abstraction is
good or bad (because I don't have time to do it justice today), but for the
sake of disclosure, I am about 80% sure it's unnecessary except in very
limited circumstances.  I much more favor the idea of business logic servers
as Aaron suggests.

That being said, I want to be very clear about the dangers of this
particular approach: it means that whenever you want a field, you should
always re-initialize the record, because if you call any other procedure,
that procedure might change the current record. 

That is, when getting data, you must have the fetch followed by all field
gets.  You cannot separate them unless you are absolutely certain you are
not calling any external procedures, and in today's modern modular design,
you should be calling external procedures for just about everything.

So the idea that the service program is holding a record for you is a
potential point of some serious and VERY difficult to debug errors.

Joe