> >In a before update, insert, delete trigger
> >it is possible to do
> >POST EVENT new.field_name
> >to post an event with the data contained in the field.
>
> No; events don't carry any data. They are merely named signals.

Not entirely true. There are systems that register for dynamic
events. For example, imagine a server side process (stored
procedure) that takes a few minutes to finish.

An application can fire off a thread that starts the procedure
with an application defined parameter (eg: event_id) and
register an event "FINISH_MY_PROC_9988332" where
"9988332" is the event ID.

When the procedure is finished, it could raise event (as written
in the documentation) like this:

myval = 'FINISH_MY_PROC_' || EventID;
POST_EVENT myval;

and the application could respond to the user with "bla bla
has finished" and un-register interest in the one-time-only
event.

With regards,

Martijn Tonies
Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL
Server
Upscene Productions
http://www.upscene.com