aggregation type

An aggregation is an object type or complex data type, which applies on a set of classified collections. Aggregation types may be defined as persistent or transient aggregation types.

Applying an aggregation type to an instance collection creates classified collections for each category in the classification and calculates the aggregated values. Typically, aggregated types contain a classifying attribute (base type) and a partition, wich contains the object instances belonging to the category.