Global Query Processing in the AutoMed Heterogeneous Database Environment
One of the requirements for implementing a heterogeneous database system is global query processing. The global query processor takes as input a query expressed on the constructs of a global schema of the heterogeneous database system. This query must be translated so that it is expressed over the constructs of the local database schemata. Appropriate local sub-queries are then sent to the local data sources for processing there. The global query processor must then take the results it receives from the local data sources and perform any necessary post-processing to obtain the result of the originally submitted global query.
KeywordsQuery Language Global Schema Query Optimisation Input Query Schema Transformation
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