RE: Externalizing I/O

Hi Justin,

I'm coming from a RLA perspective because the new RPG Redbook that prompted this discussion used RLA, and I think most people would agree that RLA is the dominant I/O method for RPG.

using SQL it's more easy to decouple database and application - but it could be done in RLA too: never use a PF only LFs!

I haven't given a whole of thought on this from a SQL perspective. My understanding is that the pre-compiler pulls in the column definitions, kind of like RLA record formats. Of course, with SQL you would only bring in the columns you
need so you might be OK if a non-referenced column was changed. I'm not sure a single *SRVPGM could handle all the I/O using SQL since most programs will have specific WHERE's and/or JOIN's.

the key to success is: never use tables in your application, only use it defining Views. So your physical implementation of your database is hidden from your application. You could change the implementation of your database as long as you could provide the same views with the same capabilities - and using instead triggers, you could even update nearly any view, even if the contain join operations. Your SRVPGM would use the extended view with all fields and you would have setters and getters only providing/needing a subset of data. There would be only one Module using this view, all other programms are using this SRVPGM to retrieve and manipulate the underlaying data.

And how did this end up on the Midrange list?

this is very easy done: just typing in the wrong eMail adress :))

Dieter