Advanced versioning mechanisms supporting CSCW environments

摘要

In the paper new mechanisms for databases used as kernels of CSCW applications are proposed which are necessary to improve the cooperative work of team members. These mechanisms mainly concern versioning aspects of CSCW environments. First, a particular technique for the user's workspace specification is introduced. It is used to detect and optionally to avoid all potential access conflicts between concurrently working users. Next, a new versioning technique, called the delayed versioning, is proposed. This technique supports team members working in shared environments. It substantially increases the concurrency degree of their transactions. Finally, a new technique for transaction savepoints management is proposed. It supports long-duration transactions which are often rolled back to particular points of the corresponding activities, due to unsatisfactory directions of work evolution.