The Trio Dependency System

Some properties of a specific item may be dependent upon other properties. For example, in the ceramics example, we may define the optional "Bronze Subperiods" group to be dependent on the selection of the "Periods:Bronze" option.

A simple dependency system was devised to implement these restrictions:

• Each group contains a dependency list that defines when it becomes “active."
• Groups that are not “active” will not be displayed and no selection will be available.
• Similarly, categories that have no active groups will not be displayed.

The software maintains the consistency of the Trio by ensuring that unselecting an option will unselect its dependencies.

The dependency system is utilized for both defining specific item properties and for filtering any module's collection of items according these properties. It may help reduce errors in data entry.

TIP

The dependency system is not intended to replace any formal knowledge representation system. It is a simple solution to a specific problem. Also, please note that while the software supports the Trio and its dependency mechanism, the actual design (choice of categories, groups, options, and dependencies) of a specific Trio is left to the user of any specific ODR instance. Currently this is done by editing textual configuration files.