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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