SYSTEM FOR INTERACTIVE ERROR DETECTION.

A system is described for coping with data base error detection. Intended as a 'filter' between the users and their DBMS, the Cooperative Overt Passive Error-Detection (COPE) system is designed to be easily interfaced to virtually any DBMS. The mechanisms employed in COPE to apply the error detection knowledge of the conceptual model are described. The concept of dynamic transactions, transactions constructed on-the-fly, is introduced. Dynamic transactions permit the system to create independent 'user contexts', which are single user views of a data base in the process of being updated. In addition to checking for errors within each user's actions, the system avoids having errors introduced in the data base due to undesirable interactions between users. COPE can be applied to both pre-existing data bases, and proposed data base updates. The system can operate interactively, so that users may request explanations for the errors reported to them, and obtain some forms of assistance in determining appropriate corrections.