Wednesday, May 23, 2007

SemTech conference session notes: semantic query

Notes from conference session Semantic Query: Solving the Needs of a Net-Centric Data Sharing Environment, Matt Fisher and Mike Dean. Want to pull in information from multiple sources, federated queries. Want to deliver information as a single response, timely, trustworthy, from all relevant sources. No human assistance, don't want to have to have intimate knowledge of the data source. Data spread over more than a single repository (db, excel, files, local access db), or in multiple formats - maybe proprietary. Traditional solutions: data warehousing, multi-dimensional databases, business intelligence approaches. Risks replicating the problems but on a larger scale.

Asio distributed query solution. Bridges to existing sources, initially relational db's and soap web service endpoints. Use swrl rules to map from domain ontology to data-source ontology. For RDB's, use D2RQ to map the db schema to an ontology. Semantic query decomposition - determine which db to send which parts of the query to. Not addressing "data deconfliction" in this project - mapping rules determine the golden data source for a given query element.

Use SWRL to map individuals between datasources. Translate SWRL rules to Jena rules via SweetRules. Automapper uses JDBC to introspect the db schema. Each table becomes an OWL class. Columns become properties. Based on D2RQ, not using :join or :AdditionProperty, but added :constraint.

SBWS - Semantic Bridge for Web Services. General tendency for web services to mediate access to data sources. Gives data owners more control, comfort, but makes it hard to understand the schema and hence generate the mappings. SBWS is being (will be?) adapted to include REST, using WADL to describe REST-ful services.

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