Capabilities-Based Query Rewriting in Mediator Systems

Users today are struggling to integrate a broad range of information sources providing di erent levels of query capabilities. Currently, data sources with di erent and limitedcapabilitiesare accessed either by writing rich functional wrappers for the more primitive sources, or by dealing with all sources at a lowest common denominator". This paper explores a third approach, in which a mediator ensures that sources receive queries they can handle, while still taking advantage of all of the query power of the source. We propose an architecture that enables this, and identify a key component ofthat architecture, the CapabilitiesBased Rewriter CBR. The CBR takes as input a description of the capabilities of a data source, and a query targeted for that data source. From these, the CBR determines component queries to be sent to the sources, commensurate with their abilities, and computes a plan for combining their results using joins, unions, selections, and projections. We provide a l...

• Type: Conference
• Year: 1996
• Where: PDIS
• Authors: Yannis Papakonstantinou, Ashish Gupta, Laura M. Haas
• Keywords: Data Sources, Distributed And Parallel Computing, PDIS 1996, Primitive Sources, Sources Receive Queries