Constraint maintenance in engineering design system: An active object-oriented approach

Abstract

This paper proposes a framework of engineering constraint maintenance using an active object-oriented database and solves a problem encountered when implementing the framework. The framework is proposed for the information-driven CIM system that integrates engineering constraints as well as its data. It resolves problems of the existing application-oriented constraint maintenance in which constraints are scattered in heterogeneous applications. It is possible due to the integrated management of constraints on a database using triggers, that is, on an "active" database. Existing active object-oriented databases, however, cannot properly support certain constraints that are specified on a set of classes. Those are the cases where the constraints must be maintained in the forward direction along a class composition hierarchy as well as in the backward direction. We call these kinds of problems "backward propagation problems" and investigate several approaches to resolve them using currently available techniques. Based on an approach which uses virtual classes, a new constructor, called CONSTRAINT(CCH) is proposed to support the backward propagation. Advantages of the proposed framework and the constructor for the backward propagation are demonstrated on a design constraint management that supports a control panel design. (C) 1997 Elsevier Science Ltd.