Controlling propagation of operations using attributes on relations

Controlling the propagation of operations through a collection of objects connected by various relationships has been a problem both for the object-oriented and the data base communities. Operations such as copy, destroy, print, and save must propagate to some, but not all, of the objects in a collection. Such operations can be implemented using ad hoc methods on objects, at the cost of extra work and loss of clarity. The use of propagation attributes on the relationships between objects permits a concise, intuitive specification of the manner in which operations should propagate from one object to another. These concepts have been implemented in the object-oriented language DSM and have been used to write applications.