International Business Machines Corporation

John G Adair

Bruce Gilbert Lindsay

Roger A Reinsch

Melvin R Zimowski

Robert Peter Resch

Robert J Grafe

Patricia G Selinger

Daniel J Coyle, Jr

Richard A Demers

Richard R Sanders

Dusan Ecimovic

Michael E Murphy

Robert L Sunday

Robert D Jackson

The invention establishes the context in which data exchanged between dissimilar relational database management systems can be mutually understood and preserved, and data conversions can be minimized. The invention accomplishes this by establishing layers of descriptive information which isolate machine characteristics, levels of support software, and user data descriptions. Optimized processing is achieved by processing the different descriptor levels at different times during the development and execution of the database management systems. Minimal descriptive information is exchanged between the cooperating database management systems. Any data conversions that may be necessary are done only by the receiver of the data, and only at the point where it is necessary to have the data represented in the receiver's native format for processing. For sending and receiving systems which match, data conversion is completely avoided, even when the data may have been forwarded through intermediate DBMS systems which do not match. For sending and receiving systems which do not match, data conversion is minimized. The data conversion routines and tables in each system are also minimized by requiring conversion only INTO a system's native format, never FROM its native format into some other format.

Method and combination for minimizing data conversions when data is

Heterogenous database communication system in which communicating

Application programs which are developed and scheduled within a first computing system environment are permitted to access relational data registered at a remote database management system (DBMS) operating in a second computing environment dissimilar to the first computing environment. Access to data through the DBMS from an application execution site remote from the DBMS is supported by a process, logically subordinate to the application program which maps application program data access requests to the DBMS.

Query language execution on heterogeneous database servers using a

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Austin, TX, United States of America

John G Adair