About Select Functions with Join Function data sources
A Select Function component that uses a Join Function as its data source can be processing- intensive because it is executed at run time on what can be a different set of records for each entity.
However, a Select Function can be used with the Is Member Of option in a Qualifier component. When Is Member Of is used, the selection is done once as the rules are loaded, and it is therefore much more efficient. For added efficiency, you can use the Is Member Of option to refer to records in a lookup table, which by definition are the same for all entities. Using a Select Function in this way is a method for creating table-driven rules that are easy to manipulate and modify.
For more about Is Member Of feature, see
About the Is Member Of comparison operator
Copyright IBM Corporation 2012. All Rights Reserved.