Heinz Frank

Towards an Automatic Integration of Statecharts

The integration of statecharts is part of an integration methodology for object oriented views. Statecharts are the most important language for the representation of the behaviour of objects and are used in many object oriented modeling techniques, e.g. in UML ([23]). In this paper we focus on the situation where the behaviour of an object type is represented in several statecharts, which have to be integrated into a single statechart. The presented approach allows an automatic integration process but gives the designer possibilities to make own decisions to guide the integration process and to achieve qualitative design goals.

Integration of statecharts

View integration is an effective technique for developing large conceptual database models. The universe of discourse is described from the viewpoint of different user groups or parts of the system resulting in a set of external models. In a second step these models have to be integrated into a common conceptual database schema. In this work we present a new methodology for integrating views based upon an object oriented data model, where we concentrate on the integration of the behaviour of objects, which is not supported by existing view integration methods.

Optimization of Object-Oriented Queries by Inverse Methods

For object-oriented databases we propose a new technique for optimizing queries containing method invocations. This technique is based on the definition of inverse methods and query rewriting. It can be viewed as providing computed inverted access structures like (secondary) indexes provide stored inverted access structures. This technique can be applied to methods which can be fully specified as functions and to the usual comparison operations in queries. We introduce an extension to ODMG-93 [1] to define inverse methods and present the optimization algorithm for homogeneous as well as for heterogeneous collections. The application of this technique can reduce the cost of query-evaluation by orders of magnitude.