Many rule-base applications are required to support evolving behavior. This may be expressed using evolving rules. This paper
describes a framework for the definition and use of temporal ECA rules. This framework supports: rule versions that may be
simultaneously applicable, the selection of a rule among several alternatives, and flexible rules in decision support systems
that employ hypothetical scenarios.
This paper presents and discusses several temporal models (transaction time model, valid time model and bi-temporal model)
of rules, and their application to various types of databases. It presents an execution model that allows the system designer
to select rules according to filters whenever different versions of rules may apply. This capability is vital for applications
such as: rule evolution in an environment that allows retroactive update
(E.g. tax system) and in decision support systems that manage hypothetical scenarios based on rules.