The Link object provides a way to create relationships between two objects by using Head and Tail properties. The Head and the Tail can each be associated with a single instance of almost any class. For example, a link object may have the Head point to a folder and the Tail point to a document. This type of relationship is in contrast to the one-to-many nature of the RCR (Referential Containment Relationship) class, which requires that the Tail point to a single folder, while the Head may point to many containable objects (any combination of documents, folders, or custom objects).
Enterprise Manager exposes the Link object class under the "Other Classes" node. Similar to other classes in Enterprise Manager, the link class may be subclassed and its properties may be examined and modified using the property grid. An application typically subclasses the link class and restricts the types of objects which can be pointed to by the Head and Tail properties based on the requirements of the application.
Head and Tail properties of a link object behave as association properties, which enable you to manage the relationship between linked objects in the object store. The following characteristics of an association property should be implemented for a link object as follows: