AQ PL/SQL Callback

The plsqlcallback data structure specifies the user-defined PL/SQL procedure, defined in the database to be invoked on message notification.

Syntax

If a notification message is expected for an raw payload enqueue then this PL/SQL callback must have the following signature:

procedure plsqlcallback(
  context  OUT RAW, 
  reginfo  OUT SYS.AQ$_REG_INFO, 
  descr    OUT SYS.AQ$_DESCRIPTOR, 
  payload  OUT RAW,
  payloadl OUT NUMBER);

Attributes

Table 4-12 AQ PL/SQL Callback Attributes

Attribute	Description
context	Specifies the context for the callback function that was passed by dbms_aq.register. See "AQ Registration Info Type".
reginfo	See "AQ Registration Info Type".
descr	See "AQ Notification Descriptor Type".
payload	If a notification message is expected for a raw payload enqueue then this contains the raw payload that was enqueued into a non persistent queue. In case of a persistent queue with raw payload this parameter will be null.
payloadl	Specifies the length of payload. If payload is null, payload1 = 0.

If the notification message is expected for a ADT payload enqueue, the PL/SQL callback must have the following signature:

procedure plsqlcallback(
  context  OUT RAW, 
  reginfo  OUT SYS.AQ$_REG_INFO, 
  descr    OUT SYS.AQ$_DESCRIPTOR, 
  payload  OUT VARCHAR2,
  payloadl OUT NUMBER);

Summary of Subprograms

Table 4-13 DBMS_AQ Package Subprograms

Subprograms	Description
ENQUEUE Procedure	Adds a message to the specified queue.
DEQUEUE Procedure	Dequeues a message from the specified queue.
LISTEN Procedure	Listen to one or more queues on behalf of a list of agents.
REGISTER Procedure	Register for message notifications
UNREGISTER Procedure	Unregister a subscription which turns off notification
POST Procedure	Posts to a anonymous subscription which allows all clients who are registered for the subscription to get notifications.
BIND_AGENT Procedure	Creates an entry for an AQ agent in the LDAP directory
UNBIND_AGENT Procedure	Removes an entry for an AQ agent from the LDAP directory

Note: The DBMS_AQ package does not have a purity level defined; therefore, you cannot call any procedure in this package from other procedures that have RNDS, WNDS, RNPS or WNPS constraints defined.