In the Master File, use the PROPERTY=PARENT_OF and REFERENCE=hierarchyfld attributes to define the hierarchical relationship between two fields.
To use FML hierarchies, the FOR field must either be:
In other words, the FOR field must be in a parent-child hierarchy or it must be linked to a parent-child hierarchy. The latter case allows transaction data that contains the hierarchy field to be joined to a separate data source that contains the hierarchy definition.
For related information, see Requirements for FML Hierarchies.