Anzeige
Erschienen in:
2011 | OriginalPaper | Buchkapitel
Efficient Evaluation of NOT-Twig Queries in Tree-Unaware Relational Databases
verfasst von : Kheng Hong Soh, Sourav S. Bhowmick
Erschienen in: Database Systems for Advanced Applications
Verlag: Springer Berlin Heidelberg
Aktivieren Sie unsere intelligente Suche, um passende Fachinhalte oder Patente zu finden.
Wählen Sie Textabschnitte aus um mit Künstlicher Intelligenz passenden Patente zu finden. powered by
Markieren Sie Textabschnitte, um KI-gestützt weitere passende Inhalte zu finden. powered by
Despite a large body of work on
xml
query processing in relational environment, systematic study of
not
-twig queries
has received little attention in the literature. Such queries contain not-predicates and are useful for many real-world applications. In this paper, we present an efficient strategy to evaluate
not
-twig queries on top of a dewey-based
tree-unaware
system called
Sucxent++
[11]. We extend the encoding scheme of
Sucxent++
by adding two new labels, namely
AncestorValue
and
AncestorDeweyGroup
, that enable us to
directly
filter out elements satisfying a not-predicate by comparing their
ancestor group identifiers
. In this approach, a set of elements under the same common ancestor at a specific level in the
xml
tree is assigned
same ancestor group identifier
. Based on this encoding scheme, we propose a novel
sql
translation algorithm for
not
-twig query evaluation. Real and synthetic datasets are employed to demonstrate the superiority of our approach over industrial-strength
rdbms
and native
xml
databases.