How Event Handlers are Executed

When an event handler is triggered, a temporary internal connection is made, on which the event handler is executed.

The handler is not executed on the connection that caused the handler to be triggered, and consequently statements such as MESSAGE … TO CLIENT, which interact with the client application, are not meaningful within event handlers.

See SQL Anywhere 11.0.1 > SQL Anywhere Server - Database Administration > Maintaining Your Database > Automating tasks using schedules and events > Event handling tasks > Adding an event to a database.