A Rule-Oriented Formalism for Active Temporal Databases

This paper introduces a declarative conceptual modelling formalism and a database transaction handling mechanism for active temporal database applications. The term `active temporal databases' is used in this paper to refer to databases that support historical information and in addition, provide mechanisms to express and handle constraints, derivations and actions on the stored information. The conceptual modelling languages are the Entity-Relationship-Time (ERT) model, which deals with the definition of the structural aspects of the application including time modelling and complex objects, and the Conceptual Rule Language (CRL) which deals with the definition of constraints, derivations and actions expressed on the ERT model. At the database operation level the functionality expressed by the ERT model and the CRL language is realised by the Database Rule Language (DRL) which uses trigger-condition-action rules as a generic mechanism for the specification of procedures which are execu..