Query processing in multidatabase systems

Peter Scheuermann, Eugene Inseok Chong

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


An outerjoin operation is important in the multidatabase systems, but the operation produces unnecessary null values. Resolving inconsistencies of data by an aggregation could give users misleading information, cause unnecessary data movement which increases query processing costs, and also violates the autonomy of local databases. An efficient algorithm for solving these problems in multidatabase systems is presented. We generate the answers as a multiple set by which removing the null values. We give users more accurate data information by presenting all data values from different local databases, and give users flexibility by allowing them to define their own query processing strategy for the resolution of the inconsistent data. Our approach also reduces data movement and local processing costs by identifying data which will not be included in the answer set as early as possible, thus reducing data transmission costs and local processing costs. Our principle of query processing is that we allow only necessary data movement between sites so that we can utilize local processing as much as possible and make global site processing simple by having it handle small amounts of data and use simple processing strategies.

Original languageEnglish (US)
Title of host publication1992 IEEE International Conference on Systems, Man, and Cybernetics
Subtitle of host publicationEmergent Innovations in Information Transfer Processing and Decision Making, SMC 1992
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages5
ISBN (Electronic)0780307208, 9780780307209
StatePublished - 1992
EventIEEE International Conference on Systems, Man, and Cybernetics, SMC 1992 - Chicago, United States
Duration: Oct 18 1992Oct 21 1992

Publication series

NameConference Proceedings - IEEE International Conference on Systems, Man and Cybernetics
ISSN (Print)1062-922X


OtherIEEE International Conference on Systems, Man, and Cybernetics, SMC 1992
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Human-Computer Interaction


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