This paper identifies two critical problems in providing Database Management System support for medical research environments in general and for research requirements of individual disciplines. The problems identified are that of maintaining multimedia data and providing a uniform interface for various clients. We envision the regular client as a workstation based environment supporting multimedia capabilities. This paper also discusses some of the functionality required at the client and proposes viable approaches for supporting them. The mediator concept is used for supporting a federated server.
Extant systems support only database events and in some cases a few predefined events.
Snoop supports temporal, explicit, and composite events in addition to the traditional database events. The novel aspect of our work lies not only in supporting a rich set of events and event expressions, but also in the notion of parameter contexts. Essentially, parameter contexts augment the semantics of composite events for computing their parameters. For concreteness, we present parameter computation and event detection algorithms for the relational model. Finally, in the appendix, we show how a contingency plan that includes time constraints can be supported without stepping outside of the framework proposed in this paper.