Aligning vocabularies describing dataset and services with mapping descriptions based on RML to automate and facilitate the generation of RDF dataset.

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)

6. ex:1 ex:MMLabex:works
“Anastasia Dimou”

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)

19. rr:constant
ex:located
rr:template
“http://ex.com/{lab}”
rr:template
“http://ex.com/{city}”
rr:template
“http://ex.com/{lab}”
rr:template
“http://ex.com/{lab}”
<#ResearcherMap>
<#LabMap>
rr:template “{firstname} {surname}”
rr:termType rr:Literal

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

34. Input
data
Input
data
Input
data
Output
RDF
Mapping
module
RML
Processor
Map
doc

35. 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

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?

42. file.xml
XML
data
Output
RDF
Mapping
module
RML
Processor
Map
doc
Retrieval
module
Support Local File(s)

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)

44. file.xml
WEBAPI
DCAT
XML
data
Output
RDF
Mapping
module
RML
Processor
Map
doc
Retrieval
module
Source
description
Support file(s) published on the Web

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

48. file.xml
WEBAPI
DCAT
XML
data
JSON
data
tabular
data
Output
RDF
Mapping
module
RML
Processor
Map
doc
Data
repo
WEBAPI
Hydra
Data
base
JDBC
D2RQ
Retrieval
module
Source
description

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
“…”
“…”
“…”

51. file.xml
WEBAPI
DCAT
XML
data
JSON
data
tabular
data
Output
RDF
Mapping
module
RML
Processor
Map
doc
Data
repo
WEBAPI
Hydra
Data
base
JDBC
D2RQ
Retrieval
module
Source
description
Triple
store
SPARQL

52. ex:located
ex:{lab}
dbpedia:
{city}
ex:located
ex:{lab} ex:{city}
object defined in existing RDF source(s)

53. <#Lab
Logical
Source>
ql:XPath
rr:constant
ex:located
rr:template
“http://ex.com/
{/labs/lab/short}”
rml:reference “{/…/city}”
rr:termType rr:IRI
<#LabMap>
“/labs/lab”
_:Source
<#Dbpedia
Logical
Source>
ql:XPath
“/…/result”
DBpedia
<#DBpediaMap>
ex:located
ex:{lab}
dbpedia:
{city}
“SELECT …”

54. <#Lab
Logical
Source>
ql:XPath
rr:constant
ex:located
rr:template
“http://ex.com/
{/labs/lab/short}”
rml:reference “{/…/city}”
rr:termType rr:IRI
<#LabMap>
“/labs/lab”
_:Source
<#Dbpedia
Logical
Source>
ql:XPath
“/…/result”
DBpedia
<#DBpediaMap>
ex:located
ex:{lab}
dbpedia:
{city}
“SELECT …”

55. RML Editor (http://RML.io/RMLeditor)

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

58. RML.io
Questions?
Anastasia Dimou
@natadimou