2.3.6.1.3 MAP

Data field	The field value is a collection of value pairs. One pair consists of a string key and its corresponding value. Within one collection, all keys must be unique.

Hierarchical field

The field is a map of data fields. The field supports multiple data field collections.

Each map consists of:

Key: One or several key data fields in the hierarchical structure.
Value: One or several non-key data fields, and data field collections, in the hierarchical structure.

At least one child data field must be set as key field in the hierarchical field definition. If more than one key is selected for the map collection, these fields are combined to create a composite key for the map collection.