Delta abstractions are introduced as a mechanism for managing database states during the execution of active database rules. Delta abstractions build upon the use of object deltas, capturing changes to individual objects through a system-supported, collapsible type structure. The object delta structure is implemented using object-oriented concepts such as encapsulation and inheritance so that all database objects inherit the ability to transparently create and manage delta values. Delta abstractions provide an additional layer to the database programmer for organizing object deltas according to different language components that induce database changes, such as methods and active rules. As with object deltas, delta abstractions are transparently created and maintained by the active database system. We define different types of delta abstractions as views of object deltas and illustrate how the services of delta abstractions can be used to inspect the state of active rule execution. An active rule analysis and debugging tool has been implemented to demonstrate the use of object deltas and delta abstractions for dynamic analysis of active rules at runtime.

Active database technology uses active rules, called Event-Condition-Action (ECA) rules, as an integral feature of application development. Active rules specify an event that the database monitors, a declarative condition to evaluate when the event occurs, and an action to execute when the condition is true. This paper motivates the use of active rules to develop a software application that is the result of integrating black-box software components. This approach focuses on integrating black-box JavaBeans/sup TM/ components, which generate Property Change Events when the values of its properties are modified. The changes in property values are known as deltas in the database community. DeltaBeans are introduced as a mechanism to monitor the changes or deltas to the properties of a black-box JavaBeans/sup TM/ component. This paper illustrates DeltaBeans in a simple application example and motivates the use of deltas to trigger active rules that specify application integration.