Object deltas in an active database development Environment

Although the use of deltas in relational environments is fairly well established, the use of deltas in an object-oriented database (OODB) environment has not yet been fully explored. As OODB's continue to expand in functionality to include the use of active rules and integrity constraints, the need for object deltas becomes more apparent. This is especially true for active, object-oriented environments that also include deductive or declarative capabilities that are typically associated with relational systems. In this paper we present an object delta structure as an integral part of the architecture of an active database system. The object delta structure represents deltas as a natural extension to database objects through object-oriented concepts such as inheritance, encapsulation and abstraction. Object deltas are first-class objects that may be manipulated through a given set of behavior. The structure proposed goes beyond previous object delta definitions by representing incremental changes to arbitrarily complex data structures as part of the delta object. Object deltas are represented at different levels of granularity to better support the needs of different active system functions. We describe examples of using object deltas for condition monitoring and also for effective support of run-time testing and debugging tools.