2.3.7.3   Map Group

A map group is a collection of map fields. In a map group, each row is treated as a separate data structure. Each row must have an identifier, known as the key field for the row. This may be defined as any field within the row, or a combination of fields to create a composite key that better defines the row in the data structure. Fields with parameter types WORKING or VALIDATION cannot be chosen as key field. See Section 5.3.6.1 for the different parameter types.

It is possible to mix the data types and parameter types for the fields within the map group, but it is not possible to have a map group without any defined fields. A map group may not contain other groups.