Advanced Queuing - Oracle

General Features of Advanced Queuing
two events, the correlation of the message is LOGIN for logins and LOGOUT for
logouts.
The callback function counts the login/logout events for each application process.
Note that the dispatcher process needs to connect to the database for registering the
subscriptions only. The notifications themselves can be received while the process is
disconnected from the database.
PL/SQL (DBMS_AQADM Package): Example Code
CONNECT oe/oe;
/* Create the Object Type/ADT adtmsg */
CREATE OR REPLACE TYPE adtmsg AS OBJECT (id NUMBER, data VARCHAR2(4000));
/* Create the multiconsumer nonpersistent queue in OE schema: */
EXECUTE dbms_aqadm.create_np_queue(queue_name => 'LOGON_LOGOFF',
multiple_consumers => TRUE);
/* Enable the queue for enqueue and dequeue: */
EXECUTE dbms_aqadm.start_queue(queue_name => 'LOGON_LOGOFF');
/* Nonpersistent Queue Scenario - procedure to be executed upon logon: */
CREATE OR REPLACE PROCEDURE User_Logon(app_process IN VARCHAR2)
AS
msgprop dbms_aq.message_properties_t;
enqopt dbms_aq.enqueue_options_t;
enq_msgid RAW(16);
payload RAW(1);
BEGIN
/* visibility must always be immediate for NonPersistent queues */
enqopt.visibility:=dbms_aq.IMMEDIATE;
msgprop.correlation:= 'LOGON';
msgprop.recipient_list(0) := aq$_agent(app_process, NULL, NULL);
/* payload is NULL */
dbms_aq.enqueue(
queue_name => 'LOGON_LOGOFF',
enqueue_options => enqopt,
message_properties => msgprop,
payload => payload,
msgid => enq_msgid);
END;
/* Nonpersistent queue scenario - procedure to be executed upon logoff: */
CREATE OR REPLACE PROCEDURE User_Logoff(app_process IN VARCHAR2)
8-18 Oracle9i Application Developer’s Guide - Advanced Queuing