Oracle Built-in Packages

Oracle AQ Database Objects

Oracle AQ relies on a variety of database objects to get its job done. Some objects are created for each queue table established. Other objects are created at the time that Oracle AQ is installed.

Objects Per Queue Table

When a queue table is created, Oracle AQ defines a database table to hold all the messages for all queues in that queue table, as well as a view that allows a user to both query from and change (with caution and the guidance of Oracle Support) messages stored in queues of the queue table.

The database table for queue data

The name of the database table has the following form,

<queue_table>

where queue_table is the name of the queue table created. Table 5.3 shows the columns of this view.

Table 5-3. Columns in the Database Table for Queue Data

Name	Description	Datatype
Q_NAME	Name of the queue (remember that you can have more than one queue in a queue table)	VARCHAR2(30)
MSGID	Unique identifier of the message	RAW(16)
CORRID	Optional correlation identifier value provided by the user	VARCHAR2(30)
PRIORITY	Message priority	NUMBER
STATE	Message state	NUMBER
DELAY	The point in time to which the message is delayed for dequeuing	DATE
EXPIRATION	Number of seconds in which the message will expire after its message state is set to READY	NUMBER
TIME_MANAGER_INFO	For internal use only	DATE
LOCAL_ORDER_NO	For internal use only	NUMBER
CHAIN_NO	For internal use only	NUMBER
CSCN	For internal use only	NUMBER
DSCN	For internal ...