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    National Tsing Hua University Institutional Repository > 電機資訊學院 > 資訊工程學系 > 期刊論文 >  An approach to querying multiple object databases


    Please use this identifier to cite or link to this item: http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/66123


    Title: An approach to querying multiple object databases
    Authors: Koh, Jia-Ling;Chen, Arbee L. P.
    教師: 陳良弼
    Date: 2002
    Publisher: Institute of Information Science Academia Sinica
    Relation: Journal of Information Science and Engineering,Volume 18,Issue 2,Pages 281-310,MAR 2002
    Keywords: Graph theory
    Optimization
    Integration
    Conformal mapping
    Data mining
    Computer networks
    Information retrieval
    User interfaces
    Query languages
    Object oriented programming
    Abstract: In a multidatabase system which consists of object databases, a global schema created by integrating schemas of the component databases provides a uniform interface and high level location transparency to help users retrieve data. The mapping between the global and component object schemas is complicated due to schema restructuring conducted to resolve various conflicts among component schemas before conducting schema integration. This mapping information is important for global query processing. In this paper, a mapping strategy is presented. A mapping equation is defined to denote the mappings for attributes and object instances between a virtual class and its constituent classes. In addition, a mapping graph is used to describe the mapping equation. Based on the mapping information, a mechanism for processing global queries in parallel is introduced. One processing unit is responsible for decomposing the global query into subqueries against the component databases. To handle the effects of schema restructuring, preprocessing and postprocessing units are also provided for each local DBMS. The results returned from component databases need to be integrated. The concept of object isomerism, where a real-world entity is represented by more than one object in different component databases, is considered for integrating query results.
    URI: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.102.9237
    http://www.iis.sinica.edu.tw/
    http://nthur.lib.nthu.edu.tw/dspace/handle/987654321/66123
    Appears in Collections:[資訊工程學系] 期刊論文

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