Signature extraction method in rectangular database

Abstract

The signature file access method has proved to be a convenient indexing technique. The main idea of all signature-based schemes is to reflect the essence of data items into bit pattern “signatures” and store them in a separate file, which acts as a filter to eliminate the unqualified data items for an information request. Previous work on superimposed coding in relational database systems has been characterized by signatures that are generated by records with the same size. The signature generation method is based on hashing. For a documentary database, we can consider any database as a set of objects (values and their associated attribute or class name) that are indexed by specific values (or terms). In a relational database, each tuple of arity n may be considered as a document that is indexed by exactly n different values. In this paper, we propose a signature generation method (for RSCW) for a database that is physically organized into a rectangular structure. More specifically, analytical calculations and experiments have proved that this structure minimizes false drop in the case of monoattribute requests.