MQReadAllXML function
The MQReadAllXML function returns a table containing the messages and message metadata from the WebSphere MQ location specified by receive-service using the quality of service-policy.
Performing this operation does not remove the messages from the queue associated with receive-service. If num-rows is specified, a maximum of num-rows messages is returned. If num-rows is not specified, all of the available messages are returned.
Syntax
Parameters
- receive-service
- A string containing the logical WebSphere MQ destination from where the message will be received. If specified, 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 point definitions include the name of the WebSphere MQ 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 WebSphere MQ Service Policy used to the handling this message. If specified, service-policy refers 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.
- num-rows
- A positive integer containing the maximum number of messages the function returns.
Results
The MQReadAllXML function returns a table containing messages and message metadata as described in the following table.
| Column name | Data type | Description |
|---|---|---|
| MSG | XML | The contents of the WebSphere MQ message. You can specify the length of XML data when you enable the MQ XML user-defined functions. |
| CORRELID | VARCHAR(24) | A correlation ID that you can use to relate to messages. |
| TOPIC | VARCHAR(40) | The topic the message was published with, if available. |
| QNAME | VARCHAR(48) | The name of the queue where the message was received. |
| MSGID | VARCHAR(24) | The unique identifier that WebSphere MQ assigns for a message. |
| MSGFORMAT | VARCHAR(8) | The format of the message that WebSphere MQ defines. Typical strings have a format of MQSTR. |
Examples
Example 1: All the messages from the queue that are specified by the default service DB2.DEFAULT.SERVICE are read using the default policy DB2.DEFAULT.POLICY. The messages and all the metadata are returned in a table format.
select
* from table (DB2MQ.MQREADALLXML()) t
Example 2: All messages that are specified by the service MYSERVICE by using the default policy DB2.DEFAULT.POLICY. Only the MSG and CORRELID columns are returned. The message queue is in a table format, wherein you can select the fields that you want.
select t.MSG, t.CORRELID
from table (DB2MQ.MQREADALLXML('MYSERVICE')) t
Example 3: The queue that is specified by the default service DB2.DEFAULT.SERVICE is read using the default policy DB2.DEFAULT.POLICY. Only messages with a CORRELID of 1234 are returned. Up to 10 messages are read and returned. All columns are returned.
select
* from table (DB2MQ.MQREADALLXML()) t where t.CORRELID = '1234'
Example 4: The messages that are specified by the default service DB2.DEFAULT.SERVICE are read using the default policy DB2.DEFAULT.POLICY. All columns are returned.
select * from table (DB2MQ.MQREADALLXML(10))
t