Database trigger/monitor without polling

[LittleBritaly]

I'm looking for a way to monitor a mysql table for changes without polling every second or so.

At the moment I'm using Lnet to send a message to a (local network) server, which then polls the database and prints off an order (it's the only machine on the local network with a printer).

The database is not stored locally (it's at our web url) and I'm unhappy with relying on a communication connection between the two machines on the  local network.

I'd much rather have the 'print server' be able to monitor a table / receive a push notification, is there a cleaner way to do this with Lazarus (even changing the database engine if required).

[BigChimp]

Not a Mysql guy... perhaps MySQL provides some kind of trigger mechanism which can call an external executable/connect to a port and send data/etc.

Both Firebird and PostgreSQL support events and Lazarus/FPC's sqldb (as well as Zeos, I think) offer support for that mechanism:

http://wiki.lazarus.freepascal.org/Firebird_in_action#Monitoring_Events

http://wiki.lazarus.freepascal.org/postgresql#Event_monitoring