Re: Use of the IFS

On Fri, Jan 2, 2009 at 8:52 AM, McKown, John
<John.Mckown@xxxxxxxxxxxxxxxxx> wrote:

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Charles Wilt
Sent: Friday, January 02, 2009 7:19 AM
To: Midrange Systems Technical Discussion
Subject: Re: Use of the IFS

Having the stream file version on the i isn't going to do a whole lot
for you IMHO.

I will disagree here. Transferring the data from a DB file to an stream
file would be easier if the stream file were on the i. Why? Because the
process which updates the DB file on the "i" could be extended to make
corresponding updates on the stream file. Perhaps even some sort of
"trigger" action on the update of the DB. But I am not very familiar
with how DB2 on the "i" works. I'm not very DB2 literate at all.

And I'll disagree with you <grin>. Sure you could use a trigger on
the Db file to update the stream file; that's pretty easy. However
one issue would be the fact that the IFS stream file, like any PC/UNIX
stream file can't be updated by multiple users at the same time;
whereas teh DB could be. So the app writing to the DB file might have
to wait for a lock to the stream file. Unless you take actually
updating the stream file to a background batch job.

Another problem is going the other way as you yourself point out in
the next paragraph.

What data is the warehouse modifing/adding from the PC and what
application is being used to do it?

This is the difficult part. How to "back port" the updates made to the
stream file to the DB file. I don't know enough about the i to know if
there is some sort of "hook" or "exit" which could be used to monitor
the stream file for changes.

There are some methods, you could journal the IFS stream file for
instance or have object auditing turned on.

But is it worth the trouble?

Have you looked at getting rid of the requirement for the stream file
version completly and just providing the user with a way to modify the
data in the i DB file as needed?

This would be best. Eliminate the stream file entirely by replacing it
with ODBC access or something akin to that.

A web interface might be even better. Depending on the requirements,
a little RPG-CGI app might be all you need.

Charles