TPgAlerter Class

A component that allows to register interest in and asynchronously handle event notifications posted by PostgreSQL server.

For a list of all members of this type, see TPgAlerter members.

Unit

PgAlerter

Syntax

TPgAlerter = class(TDAAlerter);

Remarks

The TPgAlerter component allows you to register interest in and asynchronously handle event notifications posted by PostgreSQL server. Notifications are posted to all clients when a client executes the NOTIFY command.

Use TPgAlerter to handle events for responding to actions and database changes made by other applications.

To get events application must register the required events. To do it set the Events property to the required events and call the Start method. TPgAlerter calls the LISTEN command to listen on specified events. When one of the registered events occurs, the OnEvent handler is called.

Note: Notifications are transaction-based. This means that the waiting connection does not get event until the transaction posting the event commits.

Inheritance Hierarchy

TDAAlerter
   TPgAlerter