"Karsten Farrell" <kfarrell_at_belgariad.com> wrote in message
news:DPZW9.42$Lo2.2_at_newssvr19.news.prodigy.com...
> Do you just want to allow any session to *set* a package variable and
> allow any session to *see* the current value of that variable? If so,
> can you provide procedures/functions in the package to:
>
> set_variable(new_value);
> cur_value := get_variable;
>
> Then grant execute on the package to the world.
>
> As long as you don't close the session that's running the package, other
> sessions can use the get/set routines.
Hmm... Don't think it works this way - every session gets its own instance
of the package and they cannot interact directly. As fas as I know, pipes,
alerts, permanent tables and message queues are the only means for
interaction between different sessions. Of these, pipes and alerts are my
favorites since recently. Pipes are transaction-independent and are pretty
easy to use. Besides, they come standard with SE, while AQ is EE option
if I'm not mistaken. With pipes, you send the data to the pipe and unload
the data off the pipe when you want it, but they have a limitation of single
reader vs multiple posters. Alerts are transaction-dependent (signaller has
to commit for alert to be sent) and alert subscribers may be blocked if they
use non-zero timeouts, but otherwise they are great for notifying interested
sessions that something of interest changed. Both pipes and alerts can be
used in triggers, difference is that a message will always get through the
pipe whatever the tx outcome, while alert will only be signalled if signaller
commits. In this particular case, alerts seem to be what OP is after. In a
trigger on table of interest, you send signals, and all interested sessions are
repeatedly checking for them with zero timeouts and, if received, refresh
or reset their state. Pipes are more suitable for logging and auditing (and
they can also be used for debugging, especially of remote stored procedures
when both pipe writer and reader are executing on the remote end of a
db link.)
--
Vladimir Zakharychev (bob@dpsp-yes.com) http://www.dpsp-yes.com
Dynamic PSP(tm) - the first true RAD toolkit for Oracle-based internet applications.
All opinions are mine and do not necessarily go in line with those of my employer.
Received on Tue Jan 21 2003 - 05:33:50 CST
