PostgreSQL - LISTEN/NOTIFY 宣告

用途:
NOTIFY:產生一個通告
LISTEN:產生通告的監聽
UNLISTEN:取消通告的監聽

系統表:
pg_listener :記錄目前監聽中的程序;


範例:

#LISTEN virtual;
#NOTIFY virtual;
------------------------
Asynchronous notification "virtual" received from server process with PID 8448.

**2007-02-22
(目前必須加 " ", 否則可能會造成 error )
http://people.planetpostgresql.org/greg/index.php?/archives/98-guid.html

http://www.postgresql.org/docs/8.2/static/sql-notify.html
http://www.postgresql.org/docs/8.2/static/sql-listen.html