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SPARQL Gateway is a J2EE web application that is included with the RDF Graph feature and is designed to make semantic data easily available to applications that support XML data sources, including Oracle Business Intelligence Enterprise Edition (OBIEE).
SPARQL Gateway manages SPARQL queries and XSLT operations, executes SPARQL queries against any arbitrary standard-compliant SPARQL endpoints, and performs necessary XSL transformations before passing the response back to applications. Applications can then consume semantic data as if it is coming from an existing data source.
SPARQL Gateway handles several challenges in exposing semantic data to a non-semantic application:
RDF syntax, SPARQL query syntax and SPARQL protocol must be understood.
The SPARQL query response syntax must be understood.
A transformation must convert a SPARQL query response to something that the application can consume.
To address these challenges, SPARQL Gateway manages SPARQL queries and XSLT operations, executes SPARQL queries against any arbitrary standard-compliant SPARQL endpoints, and performs necessary XSL transformations before passing the response back to applications. Applications can then consume semantic data as if it is coming from an existing data source.
Different triple stores or quad stores often have different capabilities. With the RDF Graph SPARQL Gateway, you get certain highly desirable capabilities, such as the ability to set a timeout on a long running query and the ability to get partial results from a complex query in a given amount of time. Waiting indefinitely for a query to finish is a challenge for end users, as is an application with a response time constraint. SPARQL Gateway provides both timeout and best effort query functions on top of a SPARQL endpoint. This effectively removes some uncertainty from consuming semantic data through SPARQL query executions. (See Specifying a Timeout Value and Specifying Best Effort Query Execution for more information.)