The Trio Dependency System

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

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 assigning properties to a specific record and filtering each module's collection of records according to the presence of these properties. The dependency system 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 Categories/Groups/Options ("Trio") system with its dependency mechanism, the actual Trio design of each module is left to the user. Currently this is done by editing textual configuration files or manipulating value in simple lookup tables (see the Software Overview section).