Re: Database notification

> No, triggers start stored procedures on the server side, but nothing
on
> the client side.

Yes, that stored procedure can send a message (like JMS
publish/subscribe) to the client. I don't know what kind of languages
MySQL supports for stored procedures. If it doesn't support java, you
might consider switching to a database that support java.

> JDBC doesn't provide this kind of mechanism. You have
> to use a timer in each client and check for changes in the database
at
> certain intervals (for instance every 10 secs or so).

Polling is a solution, but a rather primitive one.

> It helps if you
> add a table with last modification timestamps, for instance one per
> table, so that your client needs to perform only simple checks.

You would still need triggers that updates the new timestamp table. If
you use this approach I would recommend a table like this,
log(id, tablename, columnname, timestamp)
and a trigger on every other table in your database that inserts a
record in this one.

Fredrik Bertilsson
http://butler.sourceforge.net

.

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