Subject Re: [IBO] limiting concurrent users
Author staff@belding
----- Original Message -----
From: Geoff Worboys <geoff@...>
To: <>
Sent: Thursday, July 05, 2001 1:39 PM
Subject: Re: [IBO] limiting concurrent users

> > As I am about to deliver a nice little software running
> > over interbase, I am now in the situation where I have
> > to limit the number of concurrent users logged into some
> > tables (but not all the tables).
> Users do not "logon" to individual tables - databases yes, but not
> tables.
> I think the best you can hope to achieve is to build something into
> your client application that logs access details when a form is
> openned, and clears when a form is closed. Of course this will mean
> problems when the application aborts or the connection fails for some
> reason ..[...]

Here is a simple method I use:

Suppose your applications know when a user is in the place where they need
to register as a concurrent user.

When in that zone your timer runs an update procedure every 5 minutes, say,
saying the users is still logged in to the zone.

When the user exits from the zone log them out by running a procedure on the

When a user first logs into the zone delete any logged in users whose update
is 6 or more minutes old, and log the user into the zone. Count the current
number of zone users and do your prevent access logic.

The times need to be tuned to your application and your restrictions.