View Creation for Queriesin Object Oriented Databases

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A view in object oriented databasescorresponds to virtual schema with restructured generalization anddecomposition hierarchies. Numbers of view creation methodologies havebeen proposed. A major drawback of existing methodologies is that theydo not maintain the closure property. That is, the result of a querydoes not have the same semantics as embodied in the object oriented datamodel. Therefore, this paper presents a view creation methodology thatderives a class in response to a users query, integrates derived classin global schema (i.e., considers the problem of classes moving in classhierarchy) and selects the required classes from global schema to createthe view for users query. Novel idea of view creation includes: (a) anobject algebra for class derivation and customization (where the derivedclasses in terms of object instances and procedure/methods are studied),(b) maintenance of closure property, and (c) classification algorithmwhich provides mechanism to deal with the problem of a class moving in aclass hierarchy.
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