External relationships of objects represent semantic dependencies between objects that enable inter-object communication and augment the services the objects provide with role-specific behaviors. Most of the object-oriented design methodologies support the notion of external relationships at the conceptual level, but OO programming languages have no language construct to directly implement the external relationships, which are implemented as containment relationships with embedded pointers resulting in the semantics of the relationships being buried in code. Moreover, object-oriented programming languages lack a mechanism to allow a dynamic classification of objects according to the roles they play in external relationships. This paper describes a technique to treat an external relationship as a conceptually useful abstraction at the specification stage and a separately identifiable structure at the implementation stage, by providing a declarative specification and an implementation in C++ with special focus on the implementation of object roles. © 1998 John Wiley & Sons, Ltd.

A process-driven, model-based solution to corrective maintenance is described. The solution approach starts by identifying the st of ordered steps that should be performed to complete a corrective maintenance task. Once the steps in the process are clearly defined, the information needed at each step is organized into maintenance information models. A set of tools that operate on the models and provide the capabilities needed for the process of corrective maintenance are then identified. Realizing the models and providing the tools through a uniform interface lead to a software maintenance system that supports effective and reliable corrective maintenance. An overview of SAMS, a Software Analysis and Maintenance System developed based on this approach, is presented. SAMS integrates various tools that are needed to support maintenance processes including the corrective maintenance process. SAMS tools are developed on top of an object model of maintenance information realized using an object-oriented database management system

The author addresses the question of the requirements of a genuine object-oriented analysis and design methodology (OOAD). The author proposes and illustrates an approach to achieving this objective.>

The author has developed a multiuser integrated software analysis and maintenance system, called SAMS, on top of an object-oriented DBMS. SAMS models the description of the various aspects of software systems by persistent object types and implements different software tools by operations of objects. Software systems which are maintained by using SAMS are represented by object instances. SAMS tightly integrates various software analysis and maintenance functions such as cross referencing, annotating and configuration management around an automatically generated object-oriented software database system. Its high-level user interface delivers various analysis and maintenance functions to end users, without exposing its internals and implementation characteristics. Its tool set allows existing software to be loaded into the database automatically. SAMS's database schema contains approximately 400 classes with thousands of attributes and methods.>

The authors introduce a clustering concept called component aggregation which considers assemblies having the same types of parts as equivalent objects. The notion of equivalent objects is used to develop a mathematical model of composite objects. It is shown that the set of equivalence classes of objects form a Boolean algebra whose minterms represent the objects that are not considered composite at the current viewing level. The algebraic structure of composite objects serves as a basis for developing a technique for organizing composite objects and supporting materialization of explosion views. The technique provides a clustering mechanism which partitions the database into meaningful and application-oriented clusters, and allows any desired explosion view to be materialized using a minimal set of stored views. A simplified relational database for design data and a set of frequent access patterns in design applications are outlined and used to demonstrate the benefits of database organizations based on the mathematical model of composite objects.>

An implementation technique for design databases is introduced. The technique is based on the component aggregation abstraction, which ignores the details of assembly structures of objects and considers assemblies which have exactly the same type of parts as equivalent assemblies. Component aggregation allows structural properties of design objects to be explored and utilized to achieve efficient organization of design data. A mathematical model of design objects is developed, and used to demonstrate the benefits of component aggregation in the execution of frequent operations in design applications.