Signature-based structures for objects with set-valued attributes

Abstract

Aiming at the efficient retrieval of objects with set-valued attributes, we introduce three variations of a new method in order to satisfy subset and superset queries. Our approach is to combine the advantages of two access methods, that of linear Hashing and of tree-shaped methods, on which other similar methods have been previously reported as well. Performance estimation analytical functions for each particular method are presented, followed by a thorough experimental comparison of all investigated structures, where analytical and experimental results deviate 10% on the average. Finally, the results of this performance evaluation are presented and discussed, clearly showing the superiority of the new methods reaching an improvement of up to 85%. r

gStore: a graph-based SPARQL query engine

“…In our case, presence of elements in sets is captured in signatures. Thus, we have a set of signatures {s i } (representing a set of objects with set-valued attributes) and a query signature q [27]. Then, an inclusion query finds all signatures {s j } ⊆ {s i }, where q&s j = q.…”

“…The B + 1 entities of the node will be partitioned into two new nodes, where B is the maximal fanout for a node in VS * -tree. We adopt a node splitting method similar to [27]. The fundamental issue is to determine the two new nodes from among the B + 1 entities.…”

Index Data Structure for Fast Subset and Superset Queries

“…Secondly, the subset queries are studied in various sub-areas of AI for storing and querying: pre-conditions of a large set of rules [6], states in planning for storing goal sets [8] and hypotheses in data mining algorithms [9]. Finally, querying sets is an important problem in object-relational databases management systems where attributes of relations can range over sets [18,12,7,19,20].…”

“…Set-valued attributes are used for the representation of properties that range over sets of atomic values or objects. Database community has shown significant interest in indexing structures that can be used as access paths for querying set-valued attributes [18,12,7,19,20].…”

“…Tousidou et al [19] combine the advantages of two access paths: linear hashing and tree-structured methods. They show through the empirical analysis that S-tree with linear hash partitioning is efficient data structure for subset and superset queries.…”