Virtual and Real Classes

The concept of virtual and real classes is a special feature of the Knowledge Provider development layer. The concept applies to both the info object classes and the relationship classes. It supports the creation of a content model because by replicating a virtual class, more virtual classes or real classes can be defined as versions of the virtual class. When a virtual class is replicated, a duplicate of the entire class is made. Real classes inherit the instance attributes of the superior virtual IO class or relationship class. In contrast to copies, replicated real classes have a dynamic relationship to the superior virtual class. This means that changes made after replication to instance attributes of the virtual class are also made in the instance attributes of the real subordinate classes.

All the other properties of the real classes are only copied from the virtual class and have no relationship to the superior virtual class.

No instance attributes can be added to or removed from real classes that were derived from virtual classes.

Inherited attributes are highlighted and cannot be changed; copied properties are displayed in the standard font.