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The Horizontal Fragmentation (HF) is a process for reducing the number of disk access to execute a query by reducing the number of irrelevant objects accessed. In this paper, we present horizontal fragmentation based on a set of queries, and develop strategies for two versions of HF: primary and derived. Primary horizontal fragmentation of a class is(More)
The use of DL systems to add reasoning capabilities to database is now a major trend in convergence between knowledge base and database system but is still confronted with the issue of data update. DL systems provide fact additions and retractions but no real object update mechanisms. We present a semantics for update that favours attribute values to(More)
Horizontal partitioning is a logical database design technique which facilitates efficient execution of queries by reducing the irrelevant objects accessed. Given a set of most frequently executed queries on a class, the horizontal partitioning generates horizontal class fragments (each of which is a subset of object instances of the class), that meet the(More)
Semantic query optimization consists in restricting the search space in order to reduce the set of objects of interest for a query. This paper presents an indexing method based on UB-trees and a static analysis of the constraints associated to the views of the database and to any constraint expressed on attributes. The result of the static analysis is a(More)