Likewise, relations can be assigned one of the following three logical states:

A server relation is notified in creation state when the owner object has been notified in creation state and a propagate clause has been declared in the view specification. When the creation notification function is executed, notification is propagated to all the target objects of the relations that are not already subscribed to by the view through another relation. The view subscribes then to those target objects indirectly through these relations.

Subscription to these objects will be canceled when they are no longer the target of the relation, provided that no view still holds subscription to these objects either directly or through another relation.

A relation is notified in deletion state when the owner or user object has been notified in deletion state and a propagate clause has been declared in the view specification. When the deletion notification function is executed, notification is propagated to all the target objects of the relations to which the view has not subscribed through another relation.

A relation subscribed to by the view is assigned this notification state when objects have been added or removed from the relation.

Old target objects are assigned the deletion notification state, provided that the view does not hold subscription to them through another relation.

New target objects are assigned the creation notification state, provided that the view does not hold subscription to them through another relation.

Note that mappings may also be created, deleted, or updated under other circumstances, for example when conditional expressions change or to comply with the constraint rules that apply to mandatory references (see “References” in “Semantics of Dynamic View Type Specification” of the Reference Manual).