The design of an object-oriented data server for a co-operative CAD engineering environment.

A significant problem that users encounter when they must work co-operatively in a CAD engineering environment is the lack of support for data management and data control. In data management the main problems are the mismatch between data models used by users and the CAD engineering environment, the absence of mechanisms for tracking data evolution, and the lack of support for integrating data produced by multiple designers. In data control the main problems are the lack of suitable co-operative development activities, the absence of suitable data-ownership mechanisms, and the lack of control of changes-notification mechanisms. These deficiencies in existing CAD engineering environments motivated the author to provide a solution by designing and prototyping a data server. The data server is an object-oriented datastore which is equipped with a services-layer. This services-layer supports both the data management and data control aspects in a co-operative CAD engineering environment. To implement these two functions and to narrow the data model semantics gap, the object-oriented model has been extended with a construct which captures not only the structural and behavioral parts of data, but also semantic relationships among data. The four services provided by the services-layer are the versioning service which addresses the tracking of data evolution, the configuration management service designed to support co-operative work, the data-ownership service which controls and safeguards the release of data during multi-stream development, and the changes-notification service that enhances the dynamic data control capability of the CAD engineering environment