Machine-Interpretable Dataset and Service Descriptions for Heterogeneous Data Access and Retrieval
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The document discusses the RDF Mapping Language (RML) which allows for mapping various structured and semi-structured data formats to RDF for linked open data applications. It highlights the challenges of data access and retrieval, proposing RML as a solution to automate and facilitate these processes. The document also elaborates on how RML can integrate datasets from heterogeneous sources, making data more interoperable and accessible.
Machine-Interpretable Dataset and Service Descriptions for Heterogeneous Data Access and Retrieval
- 1. Machine-Interpretable Dataset and Service Descriptions for Heterogeneous Data Access & Retrieval Anastasia Dimou, Ruben Verborgh, Miel Vander Sande, Erik Mannens, Rik Van de Walle Anastasia.Dimou@UGent.be @natadimou Ghent University – iMinds – Multimedia Lab http://RML.io
- 2. Semantic Web enabled applications rely on data represented as Linked Open Data
- 3. Linked Open Data describe domain-level knowledge that is understandable by both humans and machines
- 4. Resource Description Framework (RDF) is the prevalent data model for describing Linked Open Data
- 5. predicatesubject object Resource Description Framework (RDF)
- 7. ex:1 ex:MMLabex:works “Anastasia Dimou” ex:2 ex:MMLabex:works “Ruben Verborgh”
- 8. ex:1 ex:MMLabex:works “Anastasia Dimou” ex:2 ex:MMLabex:works “Ruben Verborgh” ex:3 ex:MMLabex:works “Miel Vander Sande”
- 9. ex:1 ex:MMLabex:works “Anastasia Dimou” ex:locatedex:MMLab ex:Ghent ex:2 ex:MMLabex:works “Ruben Verborgh” ex:3 ex:MMLabex:works “Miel Vander Sande”
- 10. ex:{id} ex:{lab} ex:located ex:{lab} ex:{city} sets of triples of a dataset have repetitive patterns “{firstname} {surname}”
- 11. ex:{id} ex:{lab} sets of triples of a dataset have repetitive patterns “{firstname} {surname}” triple-oriented mapping languages formalize patterns into rules to map data to RDF ex:located ex:{lab} ex:{city}
- 12. RDF Mapping Language (RML) map any data to RDF uniform, integrable, interoperable, extensible extends the W3C-recommended R2RML http://RML.io A. Dimou, M. Vander Sande, P. Colpaert, R. Verborgh, E. Mannens, and R. Van de Walle. RML: A Generic Language for Integrated RDF Mappings of Heterogeneous Data. In Proceedings of the 7th Workshop on Linked Data on the Web (LDOW2014), 2014.
- 13. RML describes rules to map any structured data to RDF RML supports any data independently of which structure and format they have where they originally reside how they are accessed & retrieved
- 14. data access and retrieval is manually performed remains hard-coded
- 15. Mapping data any data to RDF with RML Specifying data which data form a data input how to reference data input extracts Accessing & Retrieving data data input from original source(s)
- 16. Mapping data any data to RDF with RML Specifying which data form a data input how to reference data input extracts Accessing & Retrieving data input from original source(s)
- 17. rr:constant ex:located rr:template “http://ex.com/{lab}” rr:template “http://ex.com/{city}” rr:template “http://ex.com/{id}” rr:template “http://ex.com/{lab}” rr:template “{firstname} {surname}” rr:termType rr:Literal RDF Mapping Language (RML) @prefix rr: <http://www.w3.org/ns/r2rml#>
- 18. Predicate MapSubject Map Object Map <#TriplesMap> RDF Mapping Language (RML)
- 20. Mapping data data to RDF with RML Specifying data which data form a data input how to reference data input extracts Accessing & Retrieving data data input from original source(s)
- 21. Triples Map RDF Mapping Language (RML) Predicate Object Map Subject Map Predicate Map Object Map
- 22. Triples Map RDF Mapping Language (RML) Predicate Object Map Subject Map Predicate Map Object Map Logical Source
- 23. Support data in Heterogeneous Structures tabular-structured hierarchical-structured (semi-)structured … … …
- 24. Support data in Heterogeneous Structures and Formats tabular-structured tables in DBs or CSV files … hierarchical-structured JSON or XML … (semi-)structured HTML … … … …
- 25. rr:template “http://ex.com/{id}” rr:template “http://ex.com/{lab}” <#ResearcherMap> rr:template “{firstname} {surname}” rr:termType rr:Literal id firstname surname lab 1 Anastasia Dimou MMLab 2 Ruben Verborgh MMLab 3 Miel Vander Sande MMLab support tabular-structured data
- 26. rr:constant ex:located rr:template “http://ex.com/ {/labs/lab/short}” rr:template “http://ex.com/ {/labs/lab/location/city}” <#LabMap> <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> support hierarchical-structured data
- 27. rr:constant ex:located rr:template “http://ex.com/ {/labs/lab/short}” rr:template “http://ex.com/ {/labs/lab/location/city}” <#LabMap> <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> How to reference data extracts?
- 28. Triples Map RDF Mapping Language (RML) Predicate Object Map Subject Map Predicate Map Object Map Logical Source Reference Formulation
- 29. <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> <#Lab Logical Source> ql:XPath rr:constant ex:located rr:template “http://ex.com/ {/labs/lab/short}” rr:template “http://ex.com/ {/labs/lab/location/city}” <#LabMap>
- 30. <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> <#Lab Logical Source> ql:XPath rr:constant ex:located rr:template “http://ex.com/ {/labs/lab/short}” rr:template “http://ex.com/ {/labs/lab/location/city}” <#LabMap> How to iterate over the data?
- 31. Triples Map RDF Mapping Language (RML) Predicate Object Map Subject Map Predicate Map Object Map Logical Source Reference Formulation iterator
- 32. <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> <#Lab Logical Source> ql:XPath “/labs/lab” rr:constant ex:located rr:template “http://ex.com/ {/labs/lab/short}” rr:template “http://ex.com/ {/labs/lab/location/city}” <#LabMap>
- 33. Mapping data data to RDF with RML Specifying data which data form a data source how to reference data extracts Accessing & Retrieving data data from their original sources
- 36. Data source Access interface Input data Input data Input data Output RDF Mapping module RML Processor Map doc Data source Access interface Data source Access interface Retrieval module Source description Where does this data originally come from?
- 37. Support different Locations and Access Interfaces Local File(s) Database connectivity Web source(s) RDF source(s)
- 38. Dataset and Service Vocabularies advertising in machine-interpretable fashion how to access the underlying data can also be used in combination with RML to retrieve the data input to be mapped from its original source
- 39. Support different Locations and Access Interfaces Local File(s) Database connectivity D2RQ Web source(s) (Web API/service) DCAT, CSVW, Hydra, VOiD (Dataset) RDF source(s) VOiD (Endpoint), SPARQL-SD
- 40. Triples Map RDF Mapping Language (RML) Predicate Object Map Subject Map Predicate Map Object Map Logical Source Reference Formulation iterator Source
- 41. <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> <#Lab Logical Source> ql:XPath rr:constant ex:located rr:template “http://ex.com/ {/labs/lab/short}” rr:template “http://ex.com/ {/labs/lab/location/city}” <#LabMap> “/labs/lab” _:Source Where does this data originally come from?
- 43. <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> <#Lab Logical Source> ql:XPath rr:constant ex:located rr:template “http://ex.com/ {/labs/lab/short}” rr:template “http://ex.com/ {/labs/lab/location/city}” <#LabMap> “/labs/lab” “file.xml” Support Local File(s)
- 45. <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> <#Lab Logical Source> ql:XPath dcat: distribution a dcat: Distribution “/labs/lab” _:Source Support dataset on the Web (DCAT) _:Source dcat:Dataset <http://ex.com/ file.xml> dcat: downloadUrl
- 46. file.xml WEBAPI DCAT XML data JSON data Output RDF Mapping module RML Processor Map doc Data repo WEBAPI Hydra Retrieval module Source description Support data derived from a Web API
- 47. <labs> <lab> <short>MMLab</short> <title>Multimedia Lab</title> <location> <city>Ghent</city> </location> </lab> <lab> …. </lab> … </labs> <#Lab Logical Source> ql:XPath hydra: template “http://ex.com/lab? name={labName}” “/labs/lab” _:Source Support data from a Web API (Hydra) _:Source hydra: IriTemplate
- 49. rr:template “http://ex.com/{id}” rr:template “http://ex.com/{lab}” <#ResearcherMap> rr:template “{firstname} {surname}” rr:termType rr:Literal id firstname surname lab 1 Anastasia Dimou MMLab 2 Ruben Verborgh MMLab 3 Miel Vander Sande MMLab Support tabular-structured data <#DB Logical Source> rr:SQL2008 “…” _:Source “SELECT …”
- 50. rr:template “http://ex.com/{id}” rr:template “http://ex.com/{lab}” <#ResearcherMap> rr:template “{firstname} {surname}” rr:termType rr:Literal Support tabular-structured data <#DB Logical Source> rr:SQL2008 “…” _:Source “SELECT …” “…” _:Source d2rq:Database “…” “…” “…”
- 52. ex:located ex:{lab} dbpedia: {city} ex:located ex:{lab} ex:{city} object defined in existing RDF source(s)
- 56. Mapping data any data to RDF with RML Specifying data which data form a data input how to reference data input extracts Accessing & Retrieving data data input from original source(s)
- 57. Data access, retrieval and mapping descriptions are machine-interpretable Granular robust solution based on RML which further automates and facilitates the generation of RDF representations