Download as PDF, PPTX
![LD4SC
Summer
School
7th
-‐
12th
June,
Cercedilla,
Spain
Combining
statements
<hIp://www.R4SC.net/today#building_1>
<hIp://www.R4SC.net/building#hasRoom
>
<hIp://www.R4SC.net/
today#room_1>
;
<hIp://www.R4SC.net/building#hasName
>
“Our
summer
school
building";
<hIp://www.R4SC.net/city#partOfCity
>
<hIp://ciYes.com/#cercedilla>
.
<hIp://ciYes.com/#cercedilla>
<hIp://www.R4SC.net/city#closeToCity
>
<hIp://ciYes.com/#madrid>
;
<hIp://www.R4SC.net/city#hasName
>
“Cercedilla”
.
28
Same
subject
AND
[next
statement]
Same
subject
Same
subject
AND
[next
statement]
,
!
Same
subject,
same
predicate](https://image.slidesharecdn.com/qr6yjbkq8y7cdw9kcclb-signature-332698ee356df5d856162e8b42a1b403b3ee138382374d4a4b740f854eefb3df-poli-150608125400-lva1-app6891/85/RDF-S-and-SPARQL-28-320.jpg)
![LD4SC
Summer
School
7th
-‐
12th
June,
Cercedilla,
Spain
So,
why
do
we
use
these
blank
nodes?
• Simply
because
it
is
hard
to
give
everything
an
explicit
name,
this
is
not
always
wanted
/
desirable
• For
example:
@prefix
b:
<hIp://www.R4SC.net/building#>
.
@prefix
c:
<hIp://www.R4SC.net/city#>
.
@prefix
region:
<hIp://www.R4SC.net/region#>
.
<hIp://www.R4SC.net/today#building_1>
b:hasRoom
<hIp://www.R4SC.net/today#room_1>
;
b:hasName
“Our
summer
school
building";
c:partOfCity
<hIp://ciYes.com/#cercedilla>
;
c:partOfRegion
[
region:locaYon
“NorthOfMadrid”;
region:regiontype
“Forest”]
• Likewise,
people
do
not
intend
to
define
names
for
all
kinds
of
groups
of
things
-‐>
hence
a
lot
of
blank
nodes
in
descripYons
of
collecYons
and
containers
52
Blank
node](https://image.slidesharecdn.com/qr6yjbkq8y7cdw9kcclb-signature-332698ee356df5d856162e8b42a1b403b3ee138382374d4a4b740f854eefb3df-poli-150608125400-lva1-app6891/85/RDF-S-and-SPARQL-52-320.jpg)
![LD4SC
Summer
School
7th
-‐
12th
June,
Cercedilla,
Spain
The
RDF
namespace
@prefix
rdf:
h]p://www.w3.org/1999/02/22-‐
rdf-‐syntax-‐ns#](https://image.slidesharecdn.com/qr6yjbkq8y7cdw9kcclb-signature-332698ee356df5d856162e8b42a1b403b3ee138382374d4a4b740f854eefb3df-poli-150608125400-lva1-app6891/85/RDF-S-and-SPARQL-81-320.jpg)
![LD4SC
Summer
School
7th
-‐
12th
June,
Cercedilla,
Spain
The
RDFS
namespace
@prefix
rdfs:
h]p://www.w3.org/2000/01/rdf-‐
schema#](https://image.slidesharecdn.com/qr6yjbkq8y7cdw9kcclb-signature-332698ee356df5d856162e8b42a1b403b3ee138382374d4a4b740f854eefb3df-poli-150608125400-lva1-app6891/85/RDF-S-and-SPARQL-86-320.jpg)
![LD4SC
Summer
School
7th
-‐
12th
June,
Cercedilla,
Spain
DISTINCT
Keyword
RDF
data:
@prefix
b:
<hIp://www.R4SC.net/building#>
.
@prefix
:
<hIp://www.R4SC.net/today#>
.
:room_1
b:hasPresentaYon
[
b:hasPresentaYonTitle
“RDF(S)
and
SPARQL"
]
.
:room_1
b:hasPresentaYon
[
b:hasPresentaYonTitle
“Handson
session
Generate
your
RDF”;
b:startsAt
“14:30:00”^^xsd:Yme
]
.
:room_1
b:hasPresentaYon
[
b:hasPresentaYonTitle
“Handson
session
Generate
your
RDF”;
b:startsAt
“17:00:00”^^xsd:Yme
]
.
Query
PREFIX
b:
<
hIp://www.R4SC.net/building#
>
SELECT
DISTINCT
?Ytle
WHERE
{
?x
b:hasPresentaYonTitle
?Ytle}
Result
title
“RDF(S) and
SPARQL"
“Handson session
Generate your RDF"](https://image.slidesharecdn.com/qr6yjbkq8y7cdw9kcclb-signature-332698ee356df5d856162e8b42a1b403b3ee138382374d4a4b740f854eefb3df-poli-150608125400-lva1-app6891/85/RDF-S-and-SPARQL-119-320.jpg)
![LD4SC
Summer
School
7th
-‐
12th
June,
Cercedilla,
Spain
UNION
Keyword
RDF
data:
@prefix
b:
<hIp://www.R4SC.net/building#>
.
@prefix
:
<hIp://www.R4SC.net/today#>
.
:room_1
b:hasPresentaYon
[
b:hasPresentaYonTitle
“RDF(S)
and
SPARQL"
]
.
:room_1
b:hasPresentaYon
[
b:hasPresentaYonTitle
“Handson
session
Generate
your
RDF”;
b:startsAt
“14:30:00”^^xsd:Yme
]
.
:room_1
b:hasPresentaYon
[
b:hasPresentaYonTitle
“Handson
session
Generate
your
RDF”;
b:startsAt
“17:00:00”^^xsd:Yme
]
.
_:x1
b:presentaYon
“Linking
Data”
.
Query
@prefix
b:
<hIp://www.R4SC.net/building#>
.
@prefix
:
<hIp://www.R4SC.net/today#>
.
SELECT
DISTINCT
?Ytle_1
?Ytle_2
WHERE
{
{
?p
b:hasPresentaYonTitle
?Ytle_1
}
UNION
{
?p1
b:presentaYon
?Ytle_2
}
}
title
“RDF(S) and
SPARQL"
“Handson session
Generate your RDF"
“Linking Data”
Result](https://image.slidesharecdn.com/qr6yjbkq8y7cdw9kcclb-signature-332698ee356df5d856162e8b42a1b403b3ee138382374d4a4b740f854eefb3df-poli-150608125400-lva1-app6891/85/RDF-S-and-SPARQL-120-320.jpg)
Uploaded byLD4SC
RDF(S) and SPARQL
The LD4SC Summer School, held in Cercedilla, Spain from June 7th to 12th, focuses on smart cities and linked open data, covering topics such as RDF graphs, syntax, and SPARQL querying. Participants learn fundamental concepts of RDF, including URIs, literals, and the integration of various syntaxes. The event serves as an introduction to creating and querying structured data using linked open data principles.
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RDF(S) and SPARQL
- 1. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain 1st Summer School on Smart Ci2es and Linked Open Data (LD4SC-‐15) RDF(S) and SPARQL Pieter Pauwels, Ghent University
- 2. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The cool and awesome intro movies hIps://vimeo.com/36752317 hIps://www.youtube.com/watch?v=4x_xzT5eF5Q 2
- 3. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 3
- 4. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain RDF graphs, what are they RDF graphs are DIRECTED, LABELLED GRAPHS 4 P. Pauwels, D. Van Deursen, R. Verstraeten, J. De Roo, R. De Meyer, R. Van de Walle, J. Van Campenhout. A semantic rule checking environment for building performance checking. Automation in Construction 20(5) 2011, 506-518. LABELLED DIRECTED Triple
- 5. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain RDF graphs, what are they NOT Hierarchies (cfr. XML) RelaYonal databases (cfr. MySQL, SQLServer) 5 RDF graphs are DIRECTED, LABELLED GRAPHS
- 6. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain A triple 6 Triple SUBJECT OBJECT PREDICATE
- 7. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain ConnecYng Triples 7 SUBJECT OBJECT PREDICATE OBJECT PREDICATE OBJECT PREDICATE OBJECT PREDICATE
- 8. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The result: an RDF graph 8 LABELLED DIRECTED Triple That is it: simple directed labelled graphs, always remember
- 9. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 9
- 10. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Talking the RDF language • RDF stands for Resource DescripYon Framework • RDF is a standard data model for describing web resources – Note: ‘web resources’ can make statements about anything in the real world: DBPedia, geography, building informaYon, sensors, … anything goes • RDF is designed to be read and understood by computers • RDF is not designed for being displayed to people • RDF is wriIen in XML • RDF is a W3C RecommendaYon 10 hIp://www.w3schools.com/webservices/ws_rdf_intro.asp easily used usually -‐> standardisaYon not a file format, not a syntax, not a schema, … => a data model
- 11. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The SemanYc Web stack 11 Tim Berners-Lee. WWW past & future, 2003. http://www.w3.org/2003/Talks/0922-rsoc-tbl/.
- 12. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Syntaxes for serialisaYon 12 Triple RDF/XML Turtle (TTL) NotaYon-‐3 (N3) …
- 13. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Expressiveness of syntaxes 13 http://www.w3.org/DesignIssues/diagrams/n3/venn We s2ck to Turtle today
- 14. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example TTL file @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . <hIp://www.R4SC.net/today#building_1> b:hasRoom <hIp://www.R4SC.net/today#room_1> ; b:hasName “Our summer school building"; c:partOfCity <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> c:closeToCity <hIp://ciYes.com/#madrid> ; c:hasName “Cercedilla” . 14
- 15. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example TTL graph
- 16. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The same thing in RDF/XML <?xml version="1.0" encoding="UTF-‐8"?> <rdf:RDF xmlns:b="hIp://www.R4SC.net/building#" xmlns:c="hIp://www.R4SC.net/ city#" xmlns:rdf="hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#"> <rdf:DescripYon rdf:about="hIp://www.R4SC.net/today#building_1"> <c:partOfCity rdf:resource="hIp://ciYes.com/#cercedilla"/> <b:hasName>Our summer school building</b:hasName> <b:hasRoom rdf:resource="hIp://www.R4SC.net/today#room_1"/> </rdf:DescripYon> <rdf:DescripYon rdf:about="hIp://ciYes.com/#cercedilla"> <c:hasName>Cercedilla</c:hasName> <c:closeToCity rdf:resource="hIp://ciYes.com/#madrid"/> </rdf:DescripYon> </rdf:RDF> 16
- 17. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Convert to different syntaxes Convert to/from syntaxes: hIp://rdf-‐translator.appspot.com/ Or simply build and use your own sosware tool 17
- 18. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 18
- 19. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Uniform Resource IdenYfiers URI URI URI URI URI URI URI URI URI URI URI
- 20. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain What is a URI? • URI stands for Uniform Resource IdenYfier • Purpose: Obtain globally unique idenYfiers, so that informaYon can be exchanged globally. • Structure: <hIp://www.R4SC.net/today#building_1> • Namespace needed to avoid name conflicts with tags of the same name: other tags with the name “building_1” can be defined with other namespace URIs, and an RDF reader would sYll be able to tell that they were different properYes even though they had the same tag name. 20 Namespace Name
- 21. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Full version of the URIs <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/today#room_1> <hIp://www.R4SC.net/building#hasRoom > <hIp://www.R4SC.net/building#hasName > <hIp://www.R4SC.net/city#partOfCity> <hIp://www.R4SC.net/city#closeToCity> <hIp://www.R4SC.net/city#hasName> <hIp://ciYes.com/#cercedilla> <hIp://ciYes.com/#madrid> 21
- 22. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example TTL file @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . <hIp://www.R4SC.net/today#building_1> b:hasRoom <hIp://www.R4SC.net/today#room_1> ; b:hasName “Our summer school building"; c:partOfCity <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> c:closeToCity <hIp://ciYes.com/#madrid> ; c:hasName “Cercedilla” . 22
- 23. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Prefixed URIs @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . @prefix bi: <hIp://www.R4SC.net/today#> . @prefix ci: < hIp://ciYes.com/# > . bi:building_1 bi:room_1 b:hasRoom b:hasName c:partOfCity c:closeToCity c:hasName ci:madrid ci:cercedilla 23
- 24. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain TTL file with fully qualified names <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/building#hasRoom > <hIp://www.R4SC.net/ today#room_1> ; <hIp://www.R4SC.net/building#hasName > “Our summer school building"; <hIp://www.R4SC.net/city#partOfCity > <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> <hIp://www.R4SC.net/city#closeToCity > <hIp://ciYes.com/#madrid> ; <hIp://www.R4SC.net/city#hasName > “Cercedilla” . 24 -‐> prefixes increase readibility
- 25. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 25
- 26. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Statements Statement Statement Statement Statement Statement
- 27. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Statement follows triple structure <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/city#partOfCity > <hIp://ciYes.com/#cercedilla> . 27 Triple <hIp:// www.R4SC.net/ today#building_1> <hIp://ciYes.com/ #cercedilla> <hIp://www.R4SC.net/ city#partOfCity>
- 28. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Combining statements <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/building#hasRoom > <hIp://www.R4SC.net/ today#room_1> ; <hIp://www.R4SC.net/building#hasName > “Our summer school building"; <hIp://www.R4SC.net/city#partOfCity > <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> <hIp://www.R4SC.net/city#closeToCity > <hIp://ciYes.com/#madrid> ; <hIp://www.R4SC.net/city#hasName > “Cercedilla” . 28 Same subject AND [next statement] Same subject Same subject AND [next statement] , ! Same subject, same predicate
- 29. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain List of all statements <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/ building#hasRoom > <hIp://www.R4SC.net/today#room_1> . <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/ building#hasName > “Our summer school building” . <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/city#partOfCity > <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> <hIp://www.R4SC.net/city#closeToCity > <hIp://ciYes.com/#madrid> . <hIp://ciYes.com/#cercedilla> <hIp://www.R4SC.net/city#hasName > “Cercedilla” . 29
- 30. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Statements Statement Statement Statement Statement Statement
- 31. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 31
- 32. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Recap on the URIs URI URI URI URI URI URI URI URI URI URI URI
- 33. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Literals in the statements <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/ building#hasRoom > <hIp://www.R4SC.net/today#room_1> . <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/ building#hasName > “Our summer school building” . <hIp://www.R4SC.net/today#building_1> <hIp://www.R4SC.net/city#partOfCity > <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> <hIp://www.R4SC.net/city#closeToCity > <hIp://ciYes.com/#madrid> . <hIp://ciYes.com/#cercedilla> <hIp://www.R4SC.net/city#hasName > “Cercedilla” . 33 Literal Literal
- 34. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain ConvenYonal representaYon / disYncYon from regular resources Resource Resource Resource Resource Literal Literal
- 35. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Similar yet disYnct @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . @prefix xsd: <hIp://www.w3.org/2001/XMLSchema>. <hIp://www.R4SC.net/today#building_1> b:hasName “Our summer school building” , “Our summer school building”@en , “Our summer school building”^^xsd:string 35 Untyped Typed Literal with language seWng Referring to type within specific namespace
- 36. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain What is available in xsd 36 http://www.w3.org/TR/xmlschema-2/
- 37. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain What is available in xsd 37 http://www.xml.dvint.com/docs/SchemaDataTypesQR-2.pdf
- 38. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain If you do not like xsd... Simply define your own datatypes… @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . @prefix dt: < hIp://www.R4SC.net/todaysdts#> . <hIp://www.R4SC.net/today#building_1> b:hasName “Our summer school building”^^dt:myTypeOfString
- 39. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – Collec2ons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 39
- 40. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain RepeaYng properYes • I have a property that can have mulYple values, now what? – SoluYon 1: Simply repeat the property of the resource mulYple Ymes. – SoluYon 2: Use a structured value for a literal – SoluYon 3: Use an RDF Container (Sequence, Bag, or Alt) or CollecYon (RDF List) http://patterns.dataincubator.org/book/repeated-property.html
- 41. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example for soluYon 1: simply repeaYng property @prefix b: <hIp://www.R4SC.net/building#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . <hIp://www.R4SC.net/today#room_1> b:hasPersonInside <hIp://www.R4SC.net/today#PieterPauwels> , <hIp://www.R4SC.net/today#RaulGarciaCastro> , <hIp://www.R4SC.net/ today#AsuncionGomezPerez> , <hIp://www.R4SC.net/ today#MariaPovedaVillalon> , <hIp:// www.R4SC.net/today#FilipRadulovic> .
- 42. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example for soluYon 2: Use a structured value for a literal @prefix b: <hIp://www.R4SC.net/building#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . <hIp://www.R4SC.net/today#room_1> b:hasPeopleInside “IRECOGNIZETHIS:PieterPauwels; IRECOGNIZETHIS: RaulGarciaCastro; IRECOGNIZETHIS:AsuncionGomezPerez; IRECOGNIZETHIS: MariaPovedaVillalon; IRECOGNIZETHIS: FilipRadulovic” => NOT recommended!!
- 43. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example for soluYon 3 @prefix b: <hIp://www.R4SC.net/building#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . <hIp://www.R4SC.net/today#room_1> b:hasPeopleInside ( <hIp://www.R4SC.net/today#PieterPauwels> <hIp://www.R4SC.net/today#RaulGarciaCastro> <hIp://www.R4SC.net/ today#AsuncionGomezPerez> <hIp://www.R4SC.net/ today#MariaPovedaVillalon> <hIp:// www.R4SC.net/today#FilipRadulovic> )
- 44. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain So, what are our opYons for soluYon 3? • Apart from resources and literals, it is also possible to describe ‘containers’ and ‘collecYons’ • Containers – Bags – Sequences – Alt • CollecYons – Lists used to describe groups that can ONLY contain the specified members used to describe an open groups of things (unknown length)
- 45. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Bags – Seqs – Alts ?? • Bag – Unordered – Resources or literals – Duplicate values are permiIed • Sequence (Seq) – Ordered – Resources or literals – Duplicate values are permiIed • AlternaYve (Alt) – Unordered – Resources or literals – Alterna2ves for a single property value (cfr. language alternaYves) These are the convenYons / they are ‘just’ convenYons
- 46. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain List • List – Ordered – Resources or literals – Duplicate values are permiIed – Closed collecYon – length of list is known • So, idenYcal to a sequence, except that the collecYon is closed: only the listed items are in the List, nothing else
- 47. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Back to our example @prefix b: <hIp://www.R4SC.net/building#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . <hIp://www.R4SC.net/today#room_1> b:hasPeopleInside ( <hIp://www.R4SC.net/today#PieterPauwels> <hIp://www.R4SC.net/today#RaulGarciaCastro> <hIp://www.R4SC.net/ today#AsuncionGomezPerez> <hIp://www.R4SC.net/ today#MariaPovedaVillalon> <hIp:// www.R4SC.net/today#FilipRadulovic> )
- 48. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The downside of soluYon 3 <?xml version="1.0" encoding="UTF-‐8"?> <rdf:RDF xmlns:b="hIp://www.R4SC.net/building#" xmlns:rdf="hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#"> <rdf:DescripYon rdf:about="hIp://www.R4SC.net/today#room_1"> <b:hasPeopleInside rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b1"/> </rdf:DescripYon> <rdf:DescripYon rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b4"> <rdf:first rdf:resource="hIp://www.R4SC.net/today#MariaPovedaVillalon"/> <rdf:rest rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b5"/> </rdf:DescripYon> <rdf:DescripYon rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b5"> <rdf:first rdf:resource="hIp://www.R4SC.net/today#FilipRadulovic"/> <rdf:rest rdf:resource="hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#nil"/> </rdf:DescripYon> <rdf:DescripYon rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b2"> <rdf:first rdf:resource="hIp://www.R4SC.net/today#RaulGarciaCastro"/> <rdf:rest rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b3"/> </rdf:DescripYon> <rdf:DescripYon rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b1"> <rdf:first rdf:resource="hIp://www.R4SC.net/today#PieterPauwels"/> <rdf:rest rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b2"/> </rdf:DescripYon> <rdf:DescripYon rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b3"> <rdf:rest rdf:nodeID="fabfea5436e794e259b04593dadf0c9f8b4"/> <rdf:first rdf:resource="hIp://www.R4SC.net/today#AsuncionGomezPerez"/> </rdf:DescripYon> </rdf:RDF> Blank nodes Elaborate and complex descrip2on
- 49. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain RepeaYng properYes • I have a property that can have mulYple values, now what? – SoluYon 1: Simply repeat the property of the resource mulYple Ymes. RepeaYng properYes is the simplest approach to handling mulY-‐valued relaYons. The alternaYves all have their downsides. – SoluYon 2: Use a structured value for a literal – SoluYon 3: Use an RDF Container (Sequence, Bag, or Alt) or CollecYon (RDF List) http://patterns.dataincubator.org/book/repeated-property.html
- 50. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Wait a second… Did you say ‘blank nodes’?
- 51. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain What are blank nodes? • Blank nodes are nodes that do not have URIs – No URI -‐> no semanYcs really -‐> unstable and unreliable • They are usually represented as: _:1, _:city, _:thiscanbeanythingyouwishfor, _:8936fazGUID, … • This representaYon is typically generated on-‐the-‐fly so that it is unique within the scope in which an RDF graph is opened – When opening this RDF graph the following day, even in the same scope, enYrely different names might be generated – Unstable and unreliable 51
- 52. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain So, why do we use these blank nodes? • Simply because it is hard to give everything an explicit name, this is not always wanted / desirable • For example: @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . @prefix region: <hIp://www.R4SC.net/region#> . <hIp://www.R4SC.net/today#building_1> b:hasRoom <hIp://www.R4SC.net/today#room_1> ; b:hasName “Our summer school building"; c:partOfCity <hIp://ciYes.com/#cercedilla> ; c:partOfRegion [ region:locaYon “NorthOfMadrid”; region:regiontype “Forest”] • Likewise, people do not intend to define names for all kinds of groups of things -‐> hence a lot of blank nodes in descripYons of collecYons and containers 52 Blank node
- 53. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 53
- 54. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Data integraYon now possible MyBuilding CiYes
- 55. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain We already integrated datasets!
- 56. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Linked Open Data Cloud • hIp://lod-‐cloud.net/ • datasets that have been published in Linked Data format, by contributors to the Linking Open Data community project and other individuals and organisaYons • based on metadata collected and curated by contributors to the Data Hub as well as on metadata extracted from a crawl of the Linked Data web conducted in April 2014 • AIribuYon: Linking Open Data cloud diagram 2014, by Max Schmachtenberg, ChrisYan Bizer, Anja Jentzsch and Richard Cyganiak. hIp://lod-‐cloud.net/
- 57. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain lod-‐cloud.net http://lod-cloud.net (Last version: 2014-08-30)
- 58. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain History of the LOD http://lod-cloud.net
- 59. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain LOD as of May 2007
- 60. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain LOD as of March 2009
- 61. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain !!!!AdverYsement break!!!! RDF(S) and SPARQL Pieter Pauwels More to come aser the break
- 62. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain !!!!AdverYsement break!!!! hIp://ldac-‐2015.bwk.tue.nl/
- 63. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Before the break
- 64. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain LOD as of August 2014
- 65. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Circle sizes and arrow fonts • Depending on the size of the dataset and the number of triples between datasets, the layout in the LOD cloud schema is different.
- 66. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Data integraYon now possible MyBuilding CiYes
- 67. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Status and staYsYcs • CumulaYve stats: hIp://stats.lod2.eu/ • State of the LOD cloud 2014: hIp://linkeddatacatalog.dws.informaYk.uni-‐ mannheim.de/state/ • State of the LOD cloud 2011: hIp://lod-‐cloud.net/state/
- 68. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Triple counts hIp://stats.lod2.eu/
- 69. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Stats -‐ Datasets by topical domain hIp://linkeddatacatalog.dws.informaYk.uni-‐mannheim.de/state/ Topic Datasets % Government 183 18.05% PublicaYons 96 9.47% Life sciences 83 8.19% User-‐generated content 48 4.73% Cross-‐domain 41 4.04% Media 22 2.17% Geographic 21 2.07% Social web 520 51.28% Total 1014
- 70. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Stats -‐ CategorizaYon by number of linked datasets Number of linked datasets Number of datasets more than 10 79 (7.79%) 6 to 10 81 (7.99%) 5 31 (3.06%) 4 42 (4.14%) 3 54 (5.33%) 2 106 (10.45%) 1 176 (17.36%) 0 445 (43.89%) hIp://linkeddatacatalog.dws.informaYk.uni-‐mannheim.de/state/
- 71. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Can my dataset be included? First, make sure that you publish data according to the Linked Data principles. We interpret this as: • There must be resolvable h+p:// (or h+ps://) URIs. • They must resolve, with or without content negoYaYon, to RDF data in one of the popular RDF formats (RDFa, RDF/ XML, Turtle, N-‐Triples). • The dataset must contain at least 1000 triples. • The dataset must be connected via RDF links to a dataset that is already in the diagram. This means, either your dataset must use URIs from the other dataset, or vice versam. We arbitrarily require at least 50 links. • Access of the en=re dataset must be possible via RDF crawling, via an RDF dump, or via a SPARQL endpoint. Then, add it to the Data Hub and request to be included
- 72. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The resolvable URIs Hold on, what do you mean, ‘resolvable’?
- 73. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Reminder: What is a URI? • URI stands for Unique Resource IdenYfier • Purpose: Obtain globally unique idenYfiers, so that informaYon can be exchanged globally. • Structure: <hIp://www.R4SC.net/today#building_1> • Namespace needed to avoid name conflicts with tags of the same name: other tags with the name “building_1" can be defined with other namespace URIs, and an RDF reader would sYll be able to tell that they were different properYes even though they had the same tag name. 73 Namespace Name
- 74. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain What do you mean… resolvable? • A resolvable URI is: “A URI whose resource has one or more representa=ons available via invoking HTTP GET on the URI” (source: hIp://www.w3.org/TR/2010/WD-‐sparql11-‐hIp-‐rdf-‐update-‐20100126/) 74 hIp://www.w3.org/TR/cooluris/#oldweb
- 75. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Dereferencing URIs hIp://wifo5-‐03.informaYk.uni-‐mannheim.de/bizer/pub/LinkedDataTutorial/
- 76. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain So, you are now ready to publish here
- 77. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Note: the O in LOD • This does NOT mean that RDF is “OPEN” by default • Most datasets in the LOD cloud have licence informaYon aIached • This does NOT mean that RDF is “OPEN” by default
- 78. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 78
- 79. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain What did we do so far? @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . <hIp://www.R4SC.net/today#building_1> b:hasRoom <hIp://www.R4SC.net/today#room_1> ; b:hasName “Our summer school building"; c:partOfCity <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> c:closeToCity <hIp://ciYes.com/#madrid> ; c:hasName “Cercedilla” . 79
- 80. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The SemanYc Web stack 80 Tim Berners-Lee. WWW past & future, 2003. http://www.w3.org/2003/Talks/0922-rsoc-tbl/.
- 81. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The RDF namespace @prefix rdf: h]p://www.w3.org/1999/02/22-‐ rdf-‐syntax-‐ns#
- 82. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The first few lines
- 83. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain We have actually already used it <?xml version="1.0" encoding="UTF-‐8"?> <rdf:RDF xmlns:b="hIp://www.R4SC.net/building#" xmlns:c="hIp://www.R4SC.net/ city#" xmlns:rdf="hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#"> <rdf:DescripYon rdf:about="hIp://www.R4SC.net/today#building_1"> <c:partOfCity rdf:resource="hIp://ciYes.com/#cercedilla"/> <b:hasName>Our summer school building</b:hasName> <b:hasRoom rdf:resource="hIp://www.R4SC.net/today#room_1"/> </rdf:DescripYon> <rdf:DescripYon rdf:about="hIp://ciYes.com/#cercedilla"> <c:hasName>Cercedilla</c:hasName> <c:closeToCity rdf:resource="hIp://ciYes.com/#madrid"/> </rdf:DescripYon> </rdf:RDF> 83
- 84. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Need for structured vocabularies • RDF graphs -‐> could be anything • Need for semanYcs / structured vocabularies ⇒ RDFSchema (RDFS) ⇒ Web Ontology Language (OWL)
- 85. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The SemanYc Web stack 85 Tim Berners-Lee. WWW past & future, 2003. http://www.w3.org/2003/Talks/0922-rsoc-tbl/.
- 86. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The RDFS namespace @prefix rdfs: h]p://www.w3.org/2000/01/rdf-‐ schema#
- 87. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain
- 88. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example TTL graph -‐> ambiguous / close to meaningless
- 89. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example vocabulary in TTL @prefix rdfs: <hIp://www.w3.org/2000/01/rdf-‐schema#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . b:InfrastructuralElement rdf:type rdfs:Class . b:Building rdf:type rdfs:Class ; rdfs:subClassOf b:InfrastructuralElement . b:hasRoom rdf:type rdf:Property ; rdfs:range b:Room ; rdfs:domain b:Building . 89
- 90. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The same thing in RDF/XML <?xml version="1.0" encoding="u•-‐8"?> <rdf:RDF xmlns:rdf="hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#" xmlns:rdfs="hIp://www.w3.org/2000/01/rdf-‐schema#"> <rdf:Property rdf:about="hIp://www.R4SC.net/building#hasRoom"> <rdfs:domain rdf:resource="hIp://www.R4SC.net/building#Building"/> <rdfs:range rdf:resource="hIp://www.R4SC.net/building#Room"/> </rdf:Property> <rdfs:Class rdf:about="hIp://www.R4SC.net/building#InfrastructuralElement"/> <rdfs:Class rdf:about="hIp://www.R4SC.net/building#Building"> <rdfs:subClassOf rdf:resource="hIp://www.R4SC.net/ building#InfrastructuralElement"/> </rdfs:Class> </rdf:RDF> 90
- 91. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Combining instances and vocabulary @prefix rdfs: <hIp://www.w3.org/2000/01/rdf-‐schema#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . @prefix b: <hIp://www.R4SC.net/building#> . @prefix c: <hIp://www.R4SC.net/city#> . b:InfrastructuralElement rdf:type rdfs:Class . b:Building rdf:type rdfs:Class ; rdfs:subClassOf b:InfrastructuralElement . b:hasRoom rdf:type rdf:Property ; rdfs:range b:Room ; rdfs:domain b:Building . 91 <hIp://www.R4SC.net/today#building_1> b:hasRoom <hIp://www.R4SC.net/today#room_1>; b:hasName “Our summer school building"; c:partOfCity <hIp://ciYes.com/#cercedilla> . <hIp://ciYes.com/#cercedilla> c:closeToCity <hIp://ciYes.com/#madrid> ; c:hasName “Cercedilla” .
- 92. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example TTL graph -‐> unambiguous / meaningful semanYcs
- 93. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 93
- 94. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The SemanYc Web stack 94 Tim Berners-Lee. WWW past & future, 2003. http://www.w3.org/2003/Talks/0922-rsoc-tbl/.
- 95. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain So, it’s also just an RDF graph… 95 http://www.w3.org/DesignIssues/diagrams/n3/venn We s2ck to Turtle today Let’s just quietly extend towards SPARQL as well
- 96. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 96
- 97. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain What is SPARQL • SPARQL stands for SPARQL Protocol and RDF Query Language • SPARQL is a Query Language • Find the W3C RecommendaYon page: hIp://www.w3.org/TR/rdf-‐sparql-‐query/ – Used to express queries across diverse data sources, whether the data is stored naYvely as RDF or viewed as RDF via middleware. – SPARQL contains capabiliYes for querying required and opYonal graph paIerns along with their conjuncYons and disjuncYons. – SPARQL supports extensible value tesYng and constraining queries by source RDF graph. – The results of SPARQL queries can be results sets or RDF graphs.
- 98. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The inspiraYon: SQL select A1, A2, ..., An from r1, r2, ..., rm where P
- 99. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain SPARQL template prefix a:… select concepts from datasources where { statements } order by …
- 100. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Structure of a SPARQL query • Prefix declaraYons Used to abbreviate URIs • Dataset definiYon Used to state what RDF graph(s) are being queried • A result clause Used to idenYfy what informaYon to return from the query • The query paIern Used to specify what to query for in the underlying dataset • Query modifiers, slicing, ordering, and otherwise Used to rearrange query results (post-‐processing)
- 101. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Let’s query our example graph
- 102. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example SPARQL Query PREFIX b: <hIp://www.R4SC.net/building#> . PREFIX c: <hIp://www.R4SC.net/city#> . SELECT ?city2 WHERE { ?b b:hasRoom <hIp://www.R4SC.net/today#room_1> . ?b c:partOfCity ?city . ?city c:closeToCity ?city2 } variable Regular RDF statements Regular RDF prefix declara2ons
- 103. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Processing the WHERE statement secYon • A pa+ern is matched against the RDF data • “find a set of bindings such that the subs=tu=on of variables for values creates a triple that is in the set of triples making up the graph” • Source: hIp://www.w3.org/2004/Talks/17Dec-‐sparql/ QueryLang1/all.html
- 104. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Graph matching
- 105. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The Query Result city2 <hIp://ciYes.com/#madrid>
- 106. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 106
- 107. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Example SPARQL endpoint on DBPedia The HTTP Address of the endpoint The soiware used in the server to store the triples (cfr. DBMS) Diverse op2ons to set
- 108. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Try it Try it out on the DBPedia dataset: hIp://dbpedia.org/sparql Or even beIer: host one yourself and make it available 108
- 109. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – More details • Concluding Overview 109
- 110. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Matching literals (1) RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix people: <hIp://www.R4SC.net/people#> . @prefix xsd: <hIp://www.w3.org/2001/XMLSchema#> . <hIp://www.R4SC.net/today#room_1> b:hasPersonInside "Pieter"@en . <hIp://www.R4SC.net/today#restaurant> b:hasPersonInside "Raul"^^xsd:string . <hIp://www.R4SC.net/today#airport> b:hasPersonInside "Leandro"^^people:keynotespeaker . Query SELECT ?v WHERE { ?v ?p "Pieter" } Result { }
- 111. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Matching literals (2) RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix people: <hIp://www.R4SC.net/people#> . @prefix xsd: <hIp://www.w3.org/2001/XMLSchema#> . <hIp://www.R4SC.net/today#room_1> b:hasPersonInside "Pieter"@en . <hIp://www.R4SC.net/today#restaurant> b:hasPersonInside "Raul"^^xsd:string . <hIp://www.R4SC.net/today#airport> b:hasPersonInside "Leandro"^^people:keynotespeaker . Query SELECT ?v WHERE { ?v ?p "Pieter"@en} Result { <hIp://www.R4SC.net/today#room_1> }
- 112. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Matching literals (3) RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix people: <hIp://www.R4SC.net/people#> . @prefix xsd: <hIp://www.w3.org/2001/XMLSchema#> . <hIp://www.R4SC.net/today#room_1> b:hasPersonInside "Pieter"@en . <hIp://www.R4SC.net/today#restaurant> b:hasPersonInside "Raul"^^xsd:string . <hIp://www.R4SC.net/today#airport> b:hasPersonInside "Leandro"^^people:keynotespeaker . Query SELECT ?v WHERE { ?v ?p "Leandro"^^< hIp://www.R4SC.net/people#keynotespeaker > } Result { <hIp://www.R4SC.net/today#airport > }
- 113. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Querying blank nodes RDF data: @prefix b: <hIp://www.R4SC.net/building#> . _:room1 b:hasPersonInside “Pieter" . _:room2 b:hasPersonInside “Raul" . Query PREFIX b: <hIp://www.R4SC.net/building#> SELECT ?x ?name WHERE { ?x b:hasPersonInside ?name } Result x name _:c "Pieter" _:d "Leandro" x name _:r "Pieter" _:s "Leandro" …
- 114. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain CONSTRUCT queries RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix : <hIp://www.R4SC.net/today#> . _:a b:presenterName “Pieter" . _:b b:presenterName “Raul" . :room1 b:hasPersonInside _:a . :room1 b:hasPersonInside “Raul" . :room1 rdf:type b:R4SCPresentaYonRoom Query PREFIX b: <hIp://www.R4SC.net/building#> WHERE { ?x rdf:type b:R4SCPresentaYonRoom . ?x: b:hasPersonInside ?z . ?z b:presenterName ?name } CONSTRUCT { ?x b:hasR4SCPresenter ?name } Result @prefix b: <hIp://www.R4SC.net/building#> . @prefix : <hIp://www.R4SC.net/today#> . :room1 b:hasR4SCPresenter “Pieter” . :room1 b:hasR4SCPresenter “Raul”
- 115. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain SPARQL Filters RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix : <hIp://www.R4SC.net/today#> . :room_1 b:hasPresentaYonTitle “RDF(S) and SPARQL" . :room_1 b:hasPeopleInside 28 . :room_2 b:hasPresentaYonTitle “Handson session RDF(S) and SPARQL" . :room_2 b:hasPeopleInside 23 . Query @prefix b: <hIp://www.R4SC.net/building#> . SELECT ?Ytle WHERE { ?x b:hasPresentaYonTitle ?Ytle FILTER regex(?Ytle, "^Hands") } Result title "Handson session RDF(S) and SPARQL" Many possibili2es: string matching, value restric2ons (greaterThan, etc.), DateTime restric2ons, …
- 116. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain OPTIONAL keyword RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix : <hIp://www.R4SC.net/today#> . :room_1 b:hasPresentaYonTitle “RDF(S) and SPARQL" . :room_1 b:hasPeopleInside 28 . :room_2 b:hasPresentaYonTitle “Handson session RDF(S) and SPARQL" . :room_2 b:hasPeopleInside 23 . Query @prefix b: <hIp://www.R4SC.net/building#> . SELECT ?Ytle ?aIendees WHERE { ?x b:hasPresentaYonTitle ?Ytle . OPTIONAL { ?x b:hasPeopleInside ?aIendees. FILTER (?aIendees > 25) } } Result title attendees "RDF(S) and SPARQL" 28 "Handson session RDF(S) and SPARQL" If there is a match, give the op2onal data, otherwise give the required data
- 117. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain LIMIT Keyword RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . <hIp://www.R4SC.net/today#room_1> b:hasPersonInside “PieterPauwels" , “RaulGarciaCastro" , “AsuncionGomezPerez" , “MariaPovedaVillalon", “FilipRadulovic" . Query PREFIX b: <hIp://www.R4SC.net/building#> SELECT ?name WHERE { ?x b:hasPersonInside ?name } LIMIT 2 Result name “PieterPauwels" “RaulGarciaCastro"
- 118. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain ORDER BY RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix rdf: <hIp://www.w3.org/1999/02/22-‐rdf-‐syntax-‐ns#> . <hIp://www.R4SC.net/today#room_1> b:hasPersonInside “PieterPauwels" , “RaulGarciaCastro" , “AsuncionGomezPerez" , “MariaPovedaVillalon", “FilipRadulovic" . Query PREFIX b: <hIp://www.R4SC.net/building#> SELECT ?name WHERE { ?x b:hasPersonInside ?name } LIMIT 2 ORDER BY DESC(?name) Result name “RaulGarciaCastro" “PieterPauwels"
- 119. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain DISTINCT Keyword RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix : <hIp://www.R4SC.net/today#> . :room_1 b:hasPresentaYon [ b:hasPresentaYonTitle “RDF(S) and SPARQL" ] . :room_1 b:hasPresentaYon [ b:hasPresentaYonTitle “Handson session Generate your RDF”; b:startsAt “14:30:00”^^xsd:Yme ] . :room_1 b:hasPresentaYon [ b:hasPresentaYonTitle “Handson session Generate your RDF”; b:startsAt “17:00:00”^^xsd:Yme ] . Query PREFIX b: < hIp://www.R4SC.net/building# > SELECT DISTINCT ?Ytle WHERE { ?x b:hasPresentaYonTitle ?Ytle} Result title “RDF(S) and SPARQL" “Handson session Generate your RDF"
- 120. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain UNION Keyword RDF data: @prefix b: <hIp://www.R4SC.net/building#> . @prefix : <hIp://www.R4SC.net/today#> . :room_1 b:hasPresentaYon [ b:hasPresentaYonTitle “RDF(S) and SPARQL" ] . :room_1 b:hasPresentaYon [ b:hasPresentaYonTitle “Handson session Generate your RDF”; b:startsAt “14:30:00”^^xsd:Yme ] . :room_1 b:hasPresentaYon [ b:hasPresentaYonTitle “Handson session Generate your RDF”; b:startsAt “17:00:00”^^xsd:Yme ] . _:x1 b:presentaYon “Linking Data” . Query @prefix b: <hIp://www.R4SC.net/building#> . @prefix : <hIp://www.R4SC.net/today#> . SELECT DISTINCT ?Ytle_1 ?Ytle_2 WHERE { { ?p b:hasPresentaYonTitle ?Ytle_1 } UNION { ?p1 b:presentaYon ?Ytle_2 } } title “RDF(S) and SPARQL" “Handson session Generate your RDF" “Linking Data” Result
- 121. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain But well, the only way to learn it… Try it out, for example, on the DBPedia dataset: hIp://dbpedia.org/sparql Or even beIer: host one yourself and make it available 121
- 122. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain Index • RDF graphs: the simple basis • Syntax: talking the talk – URIs – RDF Statements – Literals – CollecYons and containers • Linked (Open) Data Cloud • Adding basic structure : RDFS • Querying: SPARQL – The basis – The SPARQL endpoint – Some more complex examples • Concluding Overview 122
- 123. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain The SemanYc Web stack 123 Tim Berners-Lee. WWW past & future, 2003. http://www.w3.org/2003/Talks/0922-rsoc-tbl/.
- 124. LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain LD4SC Summer School 7th -‐ 12th June, Cercedilla, Spain 1st Summer School on Smart Ci2es and Linked Open Data (LD4SC-‐15) Thank you for your aIenYon! pipauwel.pauwels@ugent.be