|Τίτλος||Containment of Partially Specified Tree-Pattern Queries|
|Συγγραφέας||Δημήτρης Θεοδωράτος, Θεόδωρος Δαλαμάγκας, Pawel Placek, Στέφανος Σουλδάτος, Τίμος Σελλής|
|Περίληψη||D. Theodoratos, T. Dalamagas, P. Placek, S. Souldatos, T. Sellis, Containment of Partially Specified Tree-Pattern Queries, in Proceedings of the 18th International Conference on Scientific and Statistical Database Management (SSDBM'06), Vienna, Austria, July 3-5, 2006.
Nowadays, huge volumes of data, including scientific
data, are organized or exported in tree-structured form.
Querying capabilities are provided through tree-pattern
queries. The need for integrating multiple data sources with
different tree structures has driven, recently, the suggestion
of query languages that relax the complete specification of
a tree pattern.
In this paper we adopt a query language with partially
specified tree-pattern queries. A central feature of this type
of queries is that the structure can be specified fully, partially,
or not at all in a query. Important issues in query
optimization require solving the query containment problem.
We study the containment problem for partially specified
tree-pattern queries. To support the evaluation of such
queries, we use semantically rich constructs, called dimension
graphs, which abstract structural information of the
tree-structured data. We address the problem of query containment
in the absence (absolute query containment) and
in the presence (relative query containment) of dimension
graphs, and we provide necessary and sufficient conditions
for each type of query containment. We suggest a technique
for relative query containment checking based on structural
information extracted in advance from the dimension graph.
Our approach is implemented and validated through extensive
|Κατηγορία||WWW and DBMS|
|Δημοσίευση||Proceedings of the 18th International Conference on Scientific and Statistical Database Management (SSDBM'06), Vienna, Austria, July 3-5, 2006.|
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