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    政大機構典藏 > 理學院 > 資訊科學系 > 期刊論文 >  Item 140.119/69152
    Please use this identifier to cite or link to this item: http://nccur.lib.nccu.edu.tw/handle/140.119/69152


    Title: An Approach to Querying Multiple Object Databases
    Authors: é™³è‰¯å¼¼
    CHEN,ARBEE L. P.
    KOH,JIA-LING
    Contributors: è³‡ç§‘ç³»
    Keywords: object database;multidatabase system;schema mapping strategy;global query processing;object isomerism
    Date: 2002-03
    Issue Date: 2014-08-21 15:09:08 (UTC+8)
    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.
    Relation: Journal of Information Science and Engineering (EI,SCIE),18(2),281-310
    Data Type: article
    Appears in Collections:[資訊科學系] 期刊論文

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