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Using the DAWG Test Cases with Relational Databases. Matthew Gheen mgheen@mcdonaldbradley.com October 26, 2007. Agenda. Introduction Running the tests Results Next Steps Discussion. Introduction. Semantic Bridge for Relational Databases (SBRD) Translates SPARQL to SQL
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Using the DAWG Test Cases with Relational Databases Matthew Gheen mgheen@mcdonaldbradley.com October 26, 2007
Agenda • Introduction • Running the tests • Results • Next Steps • Discussion
Introduction • Semantic Bridge for Relational Databases (SBRD) • Translates SPARQL to SQL • Only uses Jena to build models • Tool validation • Use the DAWG test cases • Creation of tool to adapt the test cases • rdf2sql
Introduction • DAWG Test Cases – Revision 1 • Set of tests used to demonstrate support for SPARQL • 170 test are relevant to SBRD • Has data • Asks a semantically correct question • Written using latest SPARQL syntax • Written by several people, all in different styles • ttl, n3 • Result and data files used for multiple tests
Running the Tests • Data conversion • Created SQL table creation and insert statements for all data files • Untyped variables _:c rdf:type foaf:Person ; foaf:mbox <mailto:fred@work.example> ; foaf:name "Fred" . _:e foaf:name "Bob" . • Multiple values for same column and row _:a foaf:name "Robert"@EN. _:a foaf:name "Roberto"@ES.
Running the Tests • Columns with more than one type _:f foaf:name "John" ; ex:empId [ ex:number "29"^^xsd:integer ] . _:g foaf:name "Dirk" ; ex:empId <http://example.org/dirk01> . • URI predicate that does not refer to another existing table. • Creates a foreign key to nowhere • <mailto:alice@work.example> is a URI • Converted to String values to prevent foreign keys to nowhere
Running the Tests • The Queries • Keywords not supported • ASK, UNSAID, DESCRIBE, and ORDER BY • Variable predicates • ?x ?y ?z • Tests for Unicode support and bad SPARQL syntax • Not SBRD functionality tests, only tests Jena. • No support for untrusted graphs • Querying data loaded from a file specified in the query
Results • 24 of 170 DAWG tests can be used for SBRD
Next Steps • Create a new set of DAWG test cases for RDF to SQL adaptors • Subset of the full test suite that is relevant to relational databases • Reusable for current and upcoming tools • Ensures SPARQL compliance as specification matures