When the Q Capture program publishes a message for publications

When you create publications, you can specify that the Q Capture program publishes a message either every time that a column in the source table changes, or only when columns that are part of a publication change.

The following sections describe the two different types of events that can cause the Q Capture program to publish a message:

Recommendation: In general, the appropriate choice is that only changes that affect a selected column should be published. However, some applications need only a portion of a row, such as the key columns, whenever a change occurs. This published information can serve as an event notification, which can trigger other actions to occur. If you publish all of the columns that are in the source table, then these two options result in the same action.

Message is sent only when columns in publications change

By default, the Q Capture program publishes a message only when the change occurs in columns that you selected for the publications.

Example: Assume that you have 100 columns in your source table and you select 25 of those columns to be published in a publication. If you specify for a message to be sent only when columns in publications change, then any time a change is made to any of the 25 columns that are part of the publication, the Q Capture program publishes an message. Any time a change is made in any of the 75 columns that are not part of the publication, the Q Capture program does not publish an message.

Message is sent every time a change occurs in the source table

You can define publications so that the Q Capture program publishes a message every time a change occurs in the source table. If you are publishing only a subset of the columns in the source table, then the Q Capture program publishes a message even if the change occurs in a column that is not part of a publication.

Example: Assume that you have 100 columns in your source table and you select 25 of those columns to be published in a publication. If you specify for a message to be sent every time a change occurs in the source table, any time that a change is made to any of the of the 100 columns in your source table, the Q Capture program publishes an message.