Polymorphic Reuse Mechanisms for Object-Oriented Database Specifications

A polymorphic approach to the incremental design and reuse of object-oriented methods and query speciications is presented. Using this approach, the eeort required for manually reprogramming methods and queries due to schema modiications can be avoided or minimized. The salient features of our approach are the use of propagation patterns and a mechanism for propagation pattern reenement. Propagation patterns can be employed as an interesting speciication formalism for modeling operational requirements in object-oriented database systems. They encourage the reuse of operational speciica-tions against the structural modiication of an object-oriented schema. Propagation pattern reenement is suited for the speciication of reusable operational modules, and for achieving reusability of propagation patterns towards the operational requirement changes. This approach has a formal basis and emphasizes structural derivation of speciications. The main innovations are in raising the level of abstraction for behavioral schema design, and for making possible the derivation of operational semantics from structural speciications. As a result, both the modularity and reusability of object-oriented schemas are increased.