The DDI4 Collections Pattern

One of the innovations in DDI4 is the introduction of the notion of a pattern, a set of abstract classes that can be realized by other classes. A class that realizes a class in a pattern has all of the properties and relationships of the pattern class, but may have additional ones as its use in a particular area of the model demands. This practice ensures that classes that have similar functionality have a similar structure, which should, in turn, make DDI4 easier to use.

The collections pattern allows for the description of simple unordered and ordered sequences and lists as well as complex orders including hierarchies, cyclical networks and directed acyclic graphs

The Collections Pattern has many realizations. It gives structure to workflows, variable groups, concept systems, code lists and classifications, processes, data records, and more.

This presentation will describe the Collections Pattern and how it has evolved over the last year. We will describe some of the pattern's realizations and will include examples of applications like the description of processes, statistical classification, and concept networks.