Supporting long-running tasks on an evolving multidatabase using interactions and events

An open nested multi-database transaction model called Interactions is proposed. Interactions sit above a layer that provide atomic, serializable global multidatabase transactions. It provides additional support for planning applications, which are long-running applications that may need to respond to changes in the underlying multidatabase. Interactions and the multidatabase architecture that they run on are described, and synchronization of Interactions is discussed. The nature of events, which the applications can use to monitor changes in the information in the multidatabase is described, and how they are detected and how to respond to them are defined. This response usually involves semantically undoing part of at least one Interaction, so a brief description of how recovery works in that situation is given