Advanced Queuing - Oracle

General Features of Advanced Queuing
Queue-Level Access Control
To propagate to a remote destination queue, the login user specified in the database
link in the address field of the agent structure should either be granted the
ENQUEUE ANY QUEUE privilege, or be granted the rights to enqueue to the
destination queue. If the login user in the database link also owns the queue tables
at the destination, no explicit privilege grant is needed.
Visual Basic (OO4O): Example Code
Use the dbexecutesql interface from the database for this functionality.
Java (JDBC): Example Code
No example is provided with this release.
Oracle supports queue-level access control for enqueue and dequeue operations.
This feature allows the application designer to protect queues created in one schema
from applications running in other schemas. The application designer needs to
grant only minimal access privileges to the applications that run outside the queue
schema. The supported access privileges on a queue are ENQUEUE, DEQUEUE and
ALL. For more information, see "Oracle Enterprise Manager Support" on page 4-8.
Scenario
The BooksOnLine application processes customer billings in its CB and CBADM
schemas. CB (Customer Billing) schema hosts the customer billing application, and
the CBADM schema hosts all related billing data stored as queue tables.
To protect the billing data, the billing application and the billing data reside in
different schemas. The billing application is allowed only to dequeue messages
from CBADM_shippedorders_que, the shipped order queue. It processes the
messages, and then enqueues new messages into CBADM_billedorders_que, the
billed order queue.
To protect the queues from other illegal operations from the application, the
following two grant calls are needed:
PL/SQL (DBMS_AQADM Package): Example Code
/* Grant dequeue privilege on the shopped orders queue to the Customer
Billing application. The CB application retrieves orders that are shipped but
not billed from the shipped orders queue. */
EXECUTE dbms_aqadm.grant_queue_privilege(
'DEQUEUE','CBADM_shippedorders_que', 'CB', FALSE);
8-4 Oracle9i Application Developer’s Guide - Advanced Queuing