1. RDB2Onto: Approach for creating semantic metadata from relational database data Martin Šeleng, Michal Laclavík, Zoltán Balogh, Ladislav Hluchý Institute of Informatics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 07 Bratislava, Slovakia e-mail: martin.seleng@savba.skmartin.seleng@savba.sk www: http://ikt.ui.sav.skhttp://ikt.ui.sav.sk 9 th International Conference June 21-22, 2007 Bratislava, Slovakia This work is supported by projects NAZOU SPVV 1025/2004, RAPORT APVT-51-024604, SEMCO-WS APVV-0391-06, VEGA 2/7098/27.

2. Problem  Building ontology based information systems, it is frequently necessary to convert or replicate data from existing information systems such as databases to the ontology based information systems  Usually data in existing information systems are stored in a relational databases

3. Approaches  Modeling languages D2R MAP R2O (not implemented yet)  Tools D2RQ (using D2R MAP language) RDQUERY (using SPARQL or RDQL queries) RDB2Onto (using RDF/OWL XML templates and SQL queries)

4. Advantages and Disadvantages of the tools approaches  Disadvantages RDQuery - uses RDQL and its successor SPARQL language which most users are not familiar D2RQ - uses own mapping language which users must learn but it is more intuitive than RDQL or SPARQL language (also automatic creation is possible by generate-mapping tool) RDB2Onto – uses template RDF/OWL XML files which structure users must learn  Advantages Better than hand made copying

5. RDB2Onto Architecture

6. Example of RDB2Onto usage: sql query and template RDF/OWL XML file <rdf:RDF xmlns:jo="http://nazou.fiit.stuba.sk/nazou/ontologies/v0.6.17/offer-job#" xmlns:inst="http://nazou.fiit.stuba.sk/nazou/ontologies/v0.6.17/offer-job-inst#" xmlns:c="http://nazou.fiit.stuba.sk/nazou/ontologies/v0.6.17/classification#" xmlns:ofr="http://nazou.fiit.stuba.sk/nazou/ontologies/v0.6.17/offer#" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:owl="http://www.w3.org/2002/07/owl#" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"> {download_date} {url} {original_doc_path} {converted_doc_path} SELECT id, url, original_doc_path, converted_doc_path, download_date, IF(lang = 'sk', 'Slovak', 'English') AS lang FROM document

7. Evaluation on 500 job offers RDQuery Execution Time [s] SPARQL Query Query Translation Mapping Process 1 Query0.0180.052 D2RQ Execution Time [s] SQL Query Query Translation Mapping Process 1 Query0.0060.030 RDB2Onto Execution Time [s] SQL Query Query Translation Mapping Process 1 Query0.0070.034

8. Thank You For Your Attention Questions?