unlisten.hlp

来自「关系型数据库 Postgresql 6.5.2」· HLP 代码 · 共 33 行

.pgaw:Help.f.t insert end "UNLISTEN" {bold} " is used to remove an existing NOTIFY registration. UNLISTEN cancels any existing registration of the current Postgres session as a listener on the notify condition notifyname. \
The special condition wildcard \"*\" cancels all listener registrations for the current session.

" {} "NOTIFY" {link notify} " contains a more extensive discussion of the use of LISTEN and NOTIFY.

" {} "Synopsis" {bold} "
" {} "
UNLISTEN \{ notifyname | * \}

" {code} "Usage" {bold} "
" {} "
postgres=> LISTEN virtual;
LISTEN
postgres=> NOTIFY virtual;
NOTIFY
ASYNC NOTIFY of 'virtual' from backend pid '12317' received

postgres=> UNLISTEN virtual;
UNLISTEN
postgres=> NOTIFY virtual;
NOTIFY
-- notice no NOTIFY event is received
postgres=>

" {code} "Notes" {bold} "

classname needs not to be a valid class name but can be any string valid as a name up to 32 characters long.

The backend does not complain if you UNLISTEN something you were not listening for. Each backend will automatically execute UNLISTEN * when exiting.

A restriction in some previous releases of Postgres that a classname which does not correspond to an actual table must be enclosed in double-quotes is no longer present.
"