In any CASE: Demeter

this article. The Demeter research was supported in part by grants from Mettler-Toledo AG, IBM Corporation and by the National Science Foundation (CCR-9102578)

Maintaining Behavioral Consistency during Schema Evolution

We examine the problem of how to ensure behavioral consistency of an object-oriented system after its schema has been updated. The problem is viewed from the perspective of both the strongly typed and the untyped language model. Solutions are compared in both models using C++ and CLOS as examples. 1 Introduction Schema evolution and transformations have recently received increasing attention in the literature in both the area of object-oriented languages and especially in the area of object-oriented database systems: [Opd92, Ber92, Ber91, Cas91, CPLZ91, DZ91, Bar91, LH90, AH88, BKKK87, PS87, SZ86]. Most of this work has been done from the object-oriented database point of view where the focus is naturally on the structural, rather than behavioral, aspects of the evolving schema. Systems such as ORION [BKKK87], GemStone [PS87], and OTGen [LH90] guarantee the correctness of the performed schema changes and reflect the impact on the persistent instances in the database (structural consis..

The Role of Polymorphic Reuse Mechanisms in Schema Evolution in an Object-Oriented Database

A seamless approach to the incremental design and reuse of object-oriented methods and query specifications is presented. We argue for avoiding or minimizing the effort required for manually reprogramming methods and queries due to schema modifications, and demonstrate how the role of polymorphic reuse mechanisms is exploited for enhancing the adaptiveness of database programs against schema evolution in an object-oriented database. The salient features of our approach are the use of propagation patterns and a mechanism for propagation pattern refinement. Propagation patterns are employed as an interesting specification formalism for modeling operational requirements. They encourage the reuse of operational specifications against the structural modification of an object-oriented schema. Propagation pattern refinement is suited for the specification of reusable operational modules. It promotes the reusability of propagation patterns towards the operational requirement changes. This app..