Snu Rdb Foundation

Samsung Electronics Co., Ltd.

Microsoft Technology Licensing, LLC

Hewlett-packard Company

Korea Advanced Institute of Science and Technology

Korea University of Technology and Education Industry-University Cooperation Foundation

Kyuseok Shim

Surajit J Chaudhuri

Jun-Ki Min

Younghoon Kim

Kyoung-Gu Woo

Chin-Wan Chung

Zhiyuan Chen

Hyoungmin Park

Yoonjae Park

Yuqing Yu

A skyline query is a query on a set of tuples which are not dominated by other tuples. The skyline query system includes a sky quad tree generator that generates a quad tree from data, and marks a leaf node, which cannot include a local skyline, as being dominated; a local skyline calculator that computes a local skyline of each leaf node, which is not marked as being dominated, in the sky quad tree; and a global skyline calculator that computes a global skyline by using the local skyline. A quad tree is a tree where each internal node has exactly four children. The skyline query is a query for calculating a skyline, a dynamic skyline, or a reverse skyline from the data, where a dynamic skyline includes dynamic attributes and a reverse skyline identifies queries corresponding to certain skyline results.

System and method for skyline queries

Provided are a method and apparatus for processing a query. The method includes generating string sets comprising a plurality of partial strings from a query string, determining a subset of the string sets as a candidate set, and searching for a document comprising the query string from the candidate set.

Method and apparatus for processing a query

A method of processing a query about an Extensible Markup Language (XML) data. The XML query processing method includes the first step of representing the XML data in the form of an XML graph, the second step of creating and updating an Adaptive Path indEX (APEX) based on frequently used paths extracted from previously processed XML queries and the XML graph, and the third step of processing an XML query using the APEX. The XML query processing is capable of improving the performance of processing the query by extracting frequently used paths from path expressions having been used as queries for XML data and updating the APEX through the use of the frequently used paths.

Method of processing query about XML data using APEX

An XML transformation tool that constructs a relational database with associated physical structures that can be populated with shredded XML data. A mapping transformation enumerator examines queries in the workload and enumerates mapping transformations that use XSD specific constraints and statistics on XML data and can be used to generate mappings from XSD to relational database schema that may lead to better performance in presence of physical design. A design tuner that searches mappings generated from a default mapping using enumerated transformations together with physical design structures associated with those mappings and selects a preferred mapping and the physical design structures. Cost estimates for performing queries in the workload are determined for the relational database implementing the mapping and associated physical design structures.

Transformation tool for mapping XML to relational database

Database applications typically need to invoke foreign functions or to access data that is not stored in the database. The invention provides a comprehensive approach to cost-based optimization of relational queries in the presence of such foreign functions. The optimization takes into account semantic information about foreign functions using a declarative rule language (e.g., SQL) to express such semantics. Procedures for applying the rewrite rules and for generating the execution space of equivalent queries are described. Procedures to obtain an optimal plan from this enriched execution space are also described. Moreover, necessary extensions to the cost model that are needed in the presence of foreign functions are described.

Method and apparatus for query optimization in a relational database

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Seoul, South Korea

Kyuseok Shim