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Assorted Database Query Methodology in DB2 Universal Data Joiner

L. Kathirvelkumaran, Dr. R. Muralidharan


DataJoiner (DJ) is an assorted database system that provides a single database image of multiple databases.  It provides transparent access to tables at remote databases through user defined aliases (nicknames) that can be accessed as if they were local tables.  DJ is also a fully functional relational database system.  A couple of salient features of the DataJoiner query optimizer are:

  1. A query submitted to DataJoiner is optimized using a cost model that takes into account the remote optimizer’s capabilities in addition to the remote query processing capabilities and
  2. If a remote database system lacks some functionality (eg: arrangement), DataJoiner compensates for it.  In this paper, we present the design of the DataJoiner query optimizer.

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Sheth A.P and J.A. Larson. Federated Database Systems for Managing Distributed, Assorted, and Autonomous Databases. ACM Computing Surveys, 22(3):183-236, March 1990.

W Du, R Krishnamurthy, and M.C Shan. Query Methodology in a Assorted DBMS. In Proceedings of the 16th International Conference on Very Large Databases, pages 277-291, 1992.

P. Gassner, G.M. Lohman, and Y Schiefer, B. Wang. Query Methodology in the IBM DB2 Family. Data Engineering Bulletin, 16(4), 1993.

L.M. Haas, D. Kossmann, E.L. Wimmers, and J. Yang. Optimizing Queries Across Diverse Data Sources. In Proceeding of the VLDB Conference, Aug 1997.

H Pirahesh, J.M Hellerstein, and W. Hassan. Extensible/Rule Based Query Rewrite Methodology in Starburst. In Proceedings of the ACM SIGMOD Conference, pages 39-48, 1992.

Rezende, F. and Hergula, K. The heterogeneity problem and middleware technology: Experiences with and performance of database gateways. In Proc. Of the Intl Conf on Very Large Databases (VLDB), New York, 1998.

M. Tork-Roth and P. Schwarz. Dont Scrap It, Wrap It! A Wrapper Architecture for Legacy Data Sources. In Proceeding of the VLDB Conference, Aug 1997.


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