Updates in a Rule-Based Language for Objects

Michael Kramer, Georg Lausen, Gunter Saake

Abstract. The integration of object-oriented concepts into deductive databases has been investigated for a certain time now. Various approaches to incorporate updates into deduction have been proposed. The current paper presents an approach which is based on object versioning}; different versions of one object may be created and referenced during an update-process. By means of such versions it becomes possible to exert explicit control on the update process during bottom-up evaluation in a rather intuitive way. The units for updates are the result sets of base methods, i.e. methods, whose results are stored in the object-base and are not defined by rules. However, the update itself may be defined by rules. Update-programs have fixpoint semantics; the fixpoint can be computed by a bottom-up evaluation according to a certain stratification.

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