Basis of a Partially Informed Distributed Database
Mark Blakey · Very Large Data Bases · 1987
This paper proposes a new class of replicated distributed databases offering high levels of dism*bution transparency for very large networks of processing sites. The class is distinguished by the restriction that processing sites possess limited rather than complete knowledge of the data objects and sites in the system. The traditional data directory is replaced by a more sophisticated knowledge model. An axiomatic flamework identifying the fundamental properties of the class is presented. A topological network model is developed front this framework as the basis of the knowledge model. The practical importance of supporting automnms sub-&mains is recognised and accommodated in the topological model. A propositional calculus is presented to sin@ify reasmhg about the physical locadon of &ta. A series of heuristics that minimize the search flort required to discover an object’s location are presented. The merits of the proposed model and search heuristics are d%monstrated by developing an outline of the main operational procedure peculiar to the proposed class: the data