A Transaction Model for Multidatabase Systems

In this paper, we present a new transaction model for multidatabase systems (MDBSs). This model captures the formalism and semantics of various extended transaction models and adopts them to an MDBS environment. The extended models constituting our transaction model are the nested transactions [4], the flexible transaction model that provides various dependency relations among transactions [7], and the model that involves a relaxed version of transaction atomicity, namely the semantic atomicity, to increase the level of concurrency [2], [5]. While including the semantics of all those transaction models, the global serializability in our execution model was ensured through the use of the ticketing method [3].