There have been many recent research efforts on temporal databases for managing current and historical data and on active databases for monitoring real-world events as well as data conditions/constraints by rules and triggers. However, the specification and management of temporal rules in active object-oriented databases has not been investigated. This paper deals with the specification and management of temporal requirements and constraints of real-world applications. We present a temporal knowledge model in which temporal rules are defined as part of the semantic specifications of object instances and object classes. We also present a temporal specification language which is characterized by its validity time specification, its trigger specification that involves time and system- and user-defined operations, and the inclusion of temporal conditions and association patterns in temporal rules. Three general types of temporal rules are distinguished: state rules for specifying the legi...
Stanley Y. W. Su, Hsin-Hsing M. Chen