Re: Real-time updates with Dev/2000

John Coll wrote:

> I want to build an appliction that runs with Windows clients and UNIX
> (Linux) Oracle database to a) use normal Dev/2000 forms to interrogate a
> database and b) displays in real-time a few counters that are constantly
> updating.

Nor Oracle, nor Windows are real time operating systems (don't know about Linux, but I doubt it).

> I can see that I could either keep the counters in the DB and see if I
> can continuously update the client displays from the DB OR "broadcast"
> the update info to the a small application on the windows PCs and
> somehow get the small app to "trigger" an update in the Oracle client
> application.

How would you cope with multiple clients, using the second scenario?

> My questions are
> a) can I get the client application to update its display every time a
> value in the DB is changed
> b) can I get another windows app to talk to the client (DDE / OLE2 /
> whatever) to agian get the client to update its display every time a new
> value is recieved
> c) which of these is "better" - or is there a better way still?

The only thing, that pops to mins is the use of a pipe; check out the DBMSPIPE package.
It still will not be real time, as the client does (as far as I know...) not have a trigger
that will respond to a change in a pipe. You can use a timer, and read the pipe
from the when-timer-expired trigger.
One advantage here, is that you could have the client set the timespan of the timer,
and thus the frequency of updates. On a slow (remote!) network, this may be appreciated.

Good luck, hope this sets off your creative cells.

Frank Received on Tue Dec 29 1998 - 09:34:41 CET