The Trio Dependency System

Some properties of a specific item may be dependent upon other properties. For example, in the previous 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 system by ensuring that unselecting an option will unselect its dependencies.

Please note that this dependency system is utilized for both categorizing any specific record property and for filtering the entire collection of records by these properties.

Therefore, it may help reduce errors in data entry.

TIP

The dependency system is a simple solution for organizing a potentially large number of properties, an issue commonly encountered in practice when dealing with a varied record set.

The software supports the Trio and its dependency mechanism. However, its actual design - choice of categories, groups, options, and dependencies - is left to the user and achieved by editing textual configuration files or simple records in a database.