Use Database to specify the component that manages a connection to the InterBase server. This connection must be open for TIBEvents to register an interest in its events with the InterBase Event manager on that server. 

When you set the Database property, TIBEvents automatically calls the database component's AddEventNotifier method so that it can register this component's events when it opens a connection (if AutoRegister is true), and so that it can unregister this component's events before closing the connection.