The MQRECEIVECLOB function returns
a message from the MQSeries® location specified by receive-service, using
the quality of service policy service-policy.
Performing this operation removes the message from the queue associated
with receive-service. If the correl-id is specified, the first message with a matching correlation identifier
will be returned. If correl-id is not specified,
the message at the head of the queue will be returned.
The data type of the result is CLOB(1M). If no messages
are available to be returned, the result is the null value.
Syntax
>>-MQRECEIVECLOB------------------------------------------------>
>--(--+----------------------------------------------------------+--)-><
'-receive-service--+-------------------------------------+-'
'-,--service-policy--+--------------+-'
'-,--correl-id-'
The schema is DB2MQ.
Function parameters
- receive-service
- A string containing the logical MQSeries destination from which the message is 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 which 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, the DB2.DEFAULT.SERVICE
is used. The maximum size of receive-service is 48 bytes.
- service-policy
- A string containing the MQSeries Service Policy to be used in the handling of 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, the default DB2.DEFAULT.POLICY is used. The maximum size
of service-policy is 48 bytes.
- correl-id
- A string containing an optional correlation identifier to be associated
with this message. The correl-id is often
specified in request and reply scenarios to associate requests with
replies. If not specified, no correlation id will be used. The maximum
size of correl-id is 24 bytes.
Authorization
One of the following authorities is required
to execute the function:
- EXECUTE privilege on the function
- DATAACCESS authority
- DBADM authority
- SQLADM authority
Default PUBLIC privilege
In a non-restrictive
database, EXECUTE privilege is granted to PUBLIC when the function
is automatically created.
Examples
Example 1: This example receives
the message at the head of the queue specified by the default service
(DB2.DEFAULT.SERVICE),
using the default policy (DB2.DEFAULT.POLICY).
VALUES MQRECEIVECLOB()
Example 2: This example receives
the message at the head of the queue specified by the service "MYSERVICE"
using the default policy (DB2.DEFAULT.POLICY).
VALUES MQRECEIVECLOB('MYSERVICE')
Example 3: This example receives
the message at the head of the queue specified by the service "MYSERVICE"
using the policy "MYPOLICY".
VALUES MQRECEIVECLOB('MYSERVICE','MYPOLICY')
Example 4: This example
receives the first message with a correlation ID that matches '1234'
from the head of the queue specified by the service "MYSERVICE" using
the policy "MYPOLICY".
VALUES MQRECEIVECLOB('MYSERVICE',MYPOLICY','1234')