RE: Question on database file

[Buck Calabro <mcalabro@xxxxxxxxxxxx>]

Assuming that your question means that you don't know what file you will be
reading until run-time, the short answer is that you can't process a file
unless you've declared it first.

The middle sized answer is that SQL has reasonable ways to access files
dynamically using PREPARE.

The longer answer is that you can declare a "generic" file in your RPG
program and perform OVRDBF/OPNQRYF in your CL to direct the generic file to
the file selected at run-time.  Processing this generic file will be
difficult because you don't know where the individual data fields start and
end.  There are various APIs available to retrieve this information, but
this brings up the question "What processing can you code into your program
for a file who's data you don't know about until run-time?"  You can't write
a program to, say, calculate VAT on a generic file, because you might get a
file like a Customer Comment file that has no currency field.  About the
only thing you can do with a generic file is display/print it.  SQL will do
that nicely, as will Query or even CPYF in a pinch.

When I come across a question like this, I usually ask "What business
problem are you trying to solve?"   That helps to clarify the direction the
answer takes.

Buck Calabro
Aptis; Albany, NY

> -----Original Message-----
> From: DINESH DALVI 
> Sent: Friday, December 17, 1999 9:39 AM
> To:   RPG400-L@midrange.com
> Subject:      Question on database file
> 
> Hi,
> 
> Could you please tell how to read a Physical File randomly when physical
> file can't be declared in RPG/CLP program?
> 
> Thanks & Regards
> 
> Dinesh
> 
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