Disconnected Operation in the Thor Object-Oriented Database System

This paper discusses issaes raised by providing disconnected operation in the Thor object-ortented database system. Disconnected operation in such a system poses new challenges because of the small size of obiects, the richness and complexity of their interconnections, the huge number of them, and the fact that they are accessed within atomic transactions. We propose three techniques to address these challenges: (l) using the database query language for hoarding; (2) using dependent commits to tentatively com´ mit transactions at the disconnected client; (3) using the high-level semantic of objects to avoidtransaction aborts.