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Th TSIMMIS Approach to Mediation: Data Models and Languages

Hector Garcia-Molina, Yannis Papakonstantinou, et al.

One-line summary: Support for integrating "related but not-quite-the-same" information sources.  Desired results are expressed as queries over semistructured self-describing data; query normalization can be used to compute the answers to queries that are not directly supported; wrappers around sources are used for homogeneity.

Overview/Main Points


They emphasize what we call "semantically similar" sources: the desired result is expressed as a query in Lorel, and the necessary "compositions" are computed using query normalization.  The fact that the sources are semantically similar to begin with is the reason a query language is a natural way to express "composition" implicitly.  In our case, we don't really have a language (yet) for expressing the desired result, but we want to express "composition" of semantically-distinct sources using an explicit composition language (similar to CLAM?).   Because the sources (services) are semantically distinct, the tasks we want to perform through automatic composition cannot be gracefully expressed in terms of a query.

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