Re: Open Access for RPG

[hr@xxxxxxxxxxxx]

Jon,

if I read this is correct ...

The RPG OA handler approach is like a simple file server for 
traditional RPGLE opcodes, but not for processing RPGLE Native 
SQL.

It could as well be done like this ....

              eval     FILE = 'MYTABLE'
              eval     OPCD = 'CHAIN'
              call     'MYHANDLER'  
              parm     FILE    // file
              parm     OPCD    // operationcode 
              parm     RTCD    // returncode
              parm     BUFFER  // datainterface
              if       OPCD = '*OK'
                ***   do something
              else
                ***   do something else
              endif

The handler (MYHANDLER program) can of course be anything from a 
good old ICF program or program that runs native and connects to a
S/36 PF doing a flat file I spec translation to a DS or be a new 
program that connects to a webservice or whatever.

The only difference is that you now has to specify the handling
program as part of a SPECIAL file on the F spec's and must specify
the interface in D specs and can use native OP codes like ... 

 chain myhandler;
 if %found;
  // do something
 else;
  // do something else
 endif;

etc.

Regards
Henrik 




Jon Paris <jon.paris@xxxxxxxxxxxxxx> 
Sent by: rpg400-l-bounces@xxxxxxxxxxxx
22-07-2010 15:57
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RPG programming on the IBM i / System i <rpg400-l@xxxxxxxxxxxx>


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Re: Open Access for RPG






Sorry Charles - I have to completely disagree with you here.

Unless you are performing set updates - not that common - most 
business applications still process a retrieved set a row at a time. 
Whether that be by retrieving the entire set as an array and then 
walking through it, or by using a cursor, or ...

Why can the OAR handler not retrieve the set and then hand it back a 
row at a time in response to read requests?

I know it will happen becuase the IBM Lab Services team already do 
this with SPECIAL files as part of their database modernization 
approach. OAR handlers are a natural and much simpler extension of 
that process.


Jon Paris

www.Partner400.com
www.SystemiDeveloper.com



On Jul 22, 2010, at 9:30 AM, rpg400-l-request@xxxxxxxxxxxx wrote:

> While you could certainly do it, I doubt it would be a good idea.
>
> The problem is that ROA is designed for RLA and you'd probably need to
> use SQL in the handler to access the remote DB.  While SQL can
> certainly return 1 record at a time, it wouldn't be very efficient.