Using the DAWG Test Cases with Relational Databases Matthew Gheen 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

 DAWG Test Cases – Revision 1 DAWG Test Cases –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 Introduction

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 ; foaf:name "Fred". _:e foaf:name "Bob". Multiple values for same column and row _:a foaf:name _:a foaf:name

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. URI predicate that does not refer to another existing table. –Creates a foreign key to nowhere is a –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 IncompatibilityNumber Failed Multiple data types for a single predicate 36 Untyped and typed data that should be in one table 1 Multiple Values for a subject predicate pair 23 URIs that refer to non-existent data 8 Unsupported keyword 50 Variable predicate 21 Test out of scope 115

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

Discussion and Questions