The MQREADCLOB function returns a message from the MQSeries® location specified
by receive-service, using the quality of
service policy defined in service-policy. Executing this operation does not remove the message from the queue
associated with receive-service, but instead
returns the message at the head of the queue.
The data type of the result is CLOB(1M). If no messages
are available to be returned, the result is the null value.
Syntax
>>-MQREADCLOB--(--+----------------------------------------+---->
'-receive-service--+-------------------+-'
'-,--service-policy-'
>--)-----------------------------------------------------------><
The schema is DB2MQ.
Function parameters
- receive-service
- A string containing the logical MQSeries destination from where the message is to be received.
If specified, the receive-service must refer
to a Service Point defined in the DB2MQ.MQSERVICE table. A service
point is a logical end-point from where a message is sent or received.
Service points definitions include the name of the MQSeries Queue Manager and Queue. If receive-service is not specified, then the DB2.DEFAULT.SERVICE will be used.
The maximum size of receive-service is 48
bytes.
- service-policy
- A string containing the MQSeries Service Policy used in handling this message. If specified,
the service-policy must refer to a Policy
defined in the DB2MQ.MQPOLICY table. A Service Policy defines a set
of quality of service options that should be applied to this messaging
operation. These options include message priority and message persistence.
If service-policy is not specified, then
the default DB2.DEFAULT.POLICY
will be used. The maximum size of service-policy is 48 bytes.
Authorization
One of the following authorities
is required to execute the function:
- EXECUTE privilege on the function
- DATAACCESS authority
- DBADM authority
- SQLADM authority
Examples
Example 1: This example reads
the message at the head of the queue specified by the default service
(DB2.DEFAULT.SERVICE), using
the default policy (DB2.DEFAULT.POLICY).
VALUES MQREADCLOB()
Example
2: This example reads the message at the head of the queue specified
by the service "MYSERVICE" using the default policy (DB2.DEFAULT.POLICY).
VALUES MQREADCLOB('MYSERVICE')
Example 3: This example reads the
message at the head of the queue specified by the service "MYSERVICE",
and using the policy "MYPOLICY".
VALUES MQREADCLOB('MYSERVICE','MYPOLICY')