A recovery method supporting user-interactive undo in database management systems

User-interactive undo is a kind of recovery facility that allows users to c orrect mistakes easily by canceling and reexecuting operations that have al ready been executed. Supporting user-interactive undo is essential for auth oring processes in new database applications such as software engineering, hypermedia, and computer-aided design. A partial rollback using savepoints supported by commercial database management systems (DBMSs), which allows o nly cancellation of executed operations, is a restricted form of user-inter active undo. Although many applications use DBMSs, they have to provide use r-interactive undo by themselves due to lack of support from the DBMSs. Sin ce implementation of user-interactive undo is quite complex, it poses signi ficant burden to application programmers. This paper proposes a new recover y method facilitating user-interactive undo in DBMSs. Such a facility relie ves the programmers of implementing user-interactive undo themselves in dev eloping DBMS applications. The method guarantees fast rollback of transacti ons that contain user-interactive undos. It also provides users with the bu lk undo operation that restores the database to a predetermined point in th e past. The bulk undo operation resembles partial rollback, but differs in that it allows redo that cancels the bulk undo. Moreover, the performance o f the method is comparable to that of the traditional recovery method in sp ite of added functionalities. (C) 1999 Elsevier Science Inc. All rights res erved.