Selection strings

A selection string is an expression that is applied to a publication to determine whether it matches a subscription. Selection strings can include wildcard characters.

When you subscribe, in addition to specifying a topic, we can specify a selection string to select publications according to their message properties.

The selection string is evaluated against the message as put by the publisher before it is modified for delivery to each subscriber. Take care when using fields in the selection string that might be modified as part of the publish operation. For example, the MQMD fields UserIdentifier, MsgId, and CorrelId.

Selection strings should not reference any of the message property fields added by the queue manager as part of the publish operation (see Publish/subscribe message properties ), except for the message property MQTopicString, which contains the topic string for the publication.