Versions and configurations in object-oriented database systems : a uniform treatment

Object-oriented database models usually allow versions only at the most specialized type/c1ass in an inheritance hierarchy. The possibility of having versions at different levels of abstraction provides a richer model and allows a more natural representation of the reality. The presence of objects and its corresponding sets of versions at different levels of a type/class hierarchy introduces the need for handling version mappings. Integrity constraints can be associated to these mappings, restricting the set of possible combinations of versions appearing at different levels of the hierarchy. Sets of versions associated with each levei of an object hierarchy often represent a very large set of possible configurations for that object, which is difficult to be handled directly by the user. In this context, adequate mechanisms are very important to define and build object configurations by means of selections applied to the set of all possible configurations, defined by the combinations of versions. This paper proposes an approach in which versions and configurations may appear at different levels of an inheritance hierarchy, and a uniform treatment is given to these two concepts

A logic programming framework for modeling temporal objects

Published versio

Proceedings of the ECSCW'95 Workshop on the Role of Version Control in CSCW Applications

The workshop entitled "The Role of Version Control in Computer Supported Cooperative Work Applications" was held on September 10, 1995 in Stockholm, Sweden in conjunction with the ECSCW'95 conference. Version control, the ability to manage relationships between successive instances of artifacts, organize those instances into meaningful structures, and support navigation and other operations on those structures, is an important problem in CSCW applications. It has long been recognized as a critical issue for inherently cooperative tasks such as software engineering, technical documentation, and authoring. The primary challenge for versioning in these areas is to support opportunistic, open-ended design processes requiring the preservation of historical perspectives in the design process, the reuse of previous designs, and the exploitation of alternative designs. The primary goal of this workshop was to bring together a diverse group of individuals interested in examining the role of versioning in Computer Supported Cooperative Work. Participation was encouraged from members of the research community currently investigating the versioning process in CSCW as well as application designers and developers who are familiar with the real-world requirements for versioning in CSCW. Both groups were represented at the workshop resulting in an exchange of ideas and information that helped to familiarize developers with the most recent research results in the area, and to provide researchers with an updated view of the needs and challenges faced by application developers. In preparing for this workshop, the organizers were able to build upon the results of their previous one entitled "The Workshop on Versioning in Hypertext" held in conjunction with the ECHT'94 conference. The following section of this report contains a summary in which the workshop organizers report the major results of the workshop. The summary is followed by a section that contains the position papers that were accepted to the workshop. The position papers provide more detailed information describing recent research efforts of the workshop participants as well as current challenges that are being encountered in the development of CSCW applications. A list of workshop participants is provided at the end of the report. The organizers would like to thank all of the participants for their contributions which were, of course, vital to the success of the workshop. We would also like to thank the ECSCW'95 conference organizers for providing a forum in which this workshop was possible

The Application of Object-Oriented Views to an Engineering Environment.

With the increasing popularity of object-oriented technology, object-oriented database systems are being used in design environments as central repositories. In this thesis, we investigate the role of versioning and the characteristics of design databases in design environments. In an effort to improve the configuration management scheme in a design environment, we also investigate the use of database views as a possible configuration tool. We propose a unified version management scheme that facilitates cooperative team work and show that the use of database views provides a powerful configuration management scheme for a design environment

A theory and model for the evolution of software services

Software services are subject to constant change and variation. To control service development, a service developer needs to know why a change was made, what are its implications and whether the change is complete. Typically, service clients do not perceive the upgraded service immediately. As a consequence, service-based applications may fail on the service client side due to changes carried out during a provider service upgrade. In order to manage changes in a meaningful and effective manner service clients must therefore be considered when service changes are introduced at the service provider's side. Otherwise such changes will most certainly result in severe application disruption. Eliminating spurious results and inconsistencies that may occur due to uncontrolled changes is therefore a necessary condition for the ability of services to evolve gracefully, ensure service stability, and handle variability in their behavior. Towards this goal, this work presents a model and a theoretical framework for the compatible evolution of services based on well-founded theories and techniques from a number of disparate fields.

A theory and model for the evolution of software services.

Software services are subject to constant change and variation. To control service development, a service developer needs to know why a change was made, what are its implications and whether the change is complete. Typically, service clients do not perceive the upgraded service immediately. As a consequence, service-based applications may fail on the service client side due to changes carried out during a provider service upgrade. In order to manage changes in a meaningful and effective manner service clients must therefore be considered when service changes are introduced at the service provider's side. Otherwise such changes will most certainly result in severe application disruption. Eliminating spurious results and inconsistencies that may occur due to uncontrolled changes is therefore a necessary condition for the ability of services to evolve gracefully, ensure service stability, and handle variability in their behavior. Towards this goal, this work presents a model and a theoretical framework for the compatible evolution of services based on well-founded theories and techniques from a number of disparate fields.