2. Tim Berners Lee on Linked Data at TED, By PhOtOnQuAnTiQuE, CC-BY-NC-SA on Flickr, http://www.flickr.com/photos/photonquantique/3272712288/
3.
4. Linked Data
1. Use URIs as names for things
2. Use HTTP URIs so that people can look up those
names.
3. When someone looks up a URI, provide useful
information, using the standards (RDF*, SPARQL)
4. Include links to other URIs. so that they can discover
more things.
Sir Tim Berners-Lee, http://www.w3.org/DesignIssues/LinkedData
7. The Web of Documents
A global network of linked documents
A place where anyone can say anything about
anything
A vast collection of human-readable knowledge
(and opinion)
Documents are linked, but links are not qualified
8. Linked Data
1. Use URIs as names for things
2. Use HTTP URIs so that people can look up those
names.
3. When someone looks up a URI, provide useful
information, using the standards (RDF*, SPARQL)
4. Include links to other URIs. so that they can discover
more things.
Sir Tim Berners-Lee, http://www.w3.org/DesignIssues/LinkedData
9. The Web of Documents
A global network of linked documents
A place where anyone can say anything about
anything
A vast collection of human-readable knowledge
(and opinion)
Documents are linked, but links are not qualified
10. The Web of Data
A global network of linked statements
A place where anyone can say anything about
anything
A vast collection of machine-readable
knowledge (and opinion)
Statements are linked, and links are qualified
18. RDF is ...
Resource Description Framework
http://www.w3.org/RDF/
A simple, powerful, data model
Used to define relationships between things
Designed to work with the architecture of the web
The data model for the Web of Data
21. http://nssdc.gsfc.nasa.gov/
Apollo 11 Command and
nmc/spacecraftDisplay.do? about Service Module
id=1969-059A
title NASA - NSSDC - Spacecraft - Details name Apollo 11 Command and Service Module
published 23 November 2009 launched 16 July 1969
size 15702 mass 28801.0
a Web Page a Spacecraft
22. Apollo 11 Command and
launchsite Cape Canaveral
Service Module
name Apollo 11 Command and Service Module name Cape Canaveral, United States
launched 16 July 1969
mass 28801.0
a Spacecraft
23. Resources...
Represent things on the web, like web pages
Represent things not on the web, like people
and places
Can represent anything at all
Named using URIs (usually)
24. Values...
Values can be ‘literal’ values or other resources
Literal values are to work with and show users
Literal values can have specific types (numbers,
dates) and language codes (en-gb, cy-gb)
Other resources are URIs to follow and find
more data
26. Apollo 11 Command and Cape Canaveral,
launchsite Cape Canaveral name
Service Module United States
27. Apollo 11 Command and Cape Canaveral,
launchsite Cape Canaveral name
Service Module United States
28. Subject Property Value
Apollo 11 Command and Cape Canaveral,
launchsite Cape Canaveral name
Service Module United States
29. Subject Property Value
Apollo 11 Command and Cape Canaveral,
launchsite Cape Canaveral name
Service Module United States
Subject Property Value
30. Statement or Triple
Subject Property Value
Apollo 11 Command and Cape Canaveral,
launchsite Cape Canaveral name
Service Module United States
Subject Property Value
31. Statement or Triple
Subject Property Value
Apollo 11 Command and Cape Canaveral,
launchsite Cape Canaveral name
Service Module United States
Subject Property Value
Statement or Triple
32. Simple Rules for Merging
URIs name the resources we are describing
Two people using the same URI are describing
the same thing
The same URI in two datasets becomes one
URI with all of the properties from both datasets
RDF data can use URIs from many different
websites
33. http://...
Apollo 11 Command and
launchsite
http://...
Cape Canaveral
Service Module
/1969-059A /cape+cana...
name Apollo 11 Command and Service Module name Cape Canaveral, United States
launched 16 July 1969
http://...
/cape+cana...
mass 28801.0
a
http://...
Spacecraft
/Spacecraft latitude N 28° 27' 31''
longitude W 80° 31' 59''
34. http://...
Apollo 11 Command and
launchsite
http://...
Cape Canaveral
Service Module
/1969-059A /cape+cana...
name Apollo 11 Command and Service Module name Cape Canaveral, United States
launched 16 July 1969 latitude N 28° 27' 31''
mass 28801.0 longitude W 80° 31' 59''
a
http://...
Spacecraft
/Spacecraft
35. Simple Rules for Merging
Graphs from several different sources can be
merged
Resources with the same URI are considered
identical
No limitations on which graphs can be merged
37. RDF...
is a Graph data model
XML is a tree data model
RDBMS is a table data model
can be easily distributed
can be easily merged
allows anyone say anything about anything
is not new
the spec is from 1999
the idea stems back to the late 1960s
39. Writing RDF
Turtle
What I’m about to show you
N-Triples
One statement per line, subset of Turtle, grep compatible
RDF/JSON
Useful for AJAX Applications and anything with else JSON support
RDFa
Writing RDF within HTML pages
RDF/XML
Machine to Machine Transfer
De-facto Standard
41. Turtle
Terse Triple Language (TTL)
http://www.w3.org/2007/02/turtle/primer/
A human-readable notation for RDF
Provides useful syntax for quickly hand-writing
RDF
Forms the basis of patterns in SPARQL
42. http://... a
http://...
/1969-059A /Spacecraft
<http://.../1969-059A> a <http://.../Spacecraft> .
43. http://...
/1969-059A
name Apollo 11 Command and Service Module
@prefix space: <http://example.com/space-schema/> .
launched 16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass 28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
a
http://...
/Spacecraft
44. http://... launchsite
http://...
/1969-059A /cape+cana...
name Apollo 11 Command and Service Module name Cape Canaveral, United States
@prefix space: <http://example.com/space-schema/> .
launched 16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass 28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
a
http://...
/Spacecraft
45. http://... launchsite
http://...
/1969-059A /cape+cana...
name Apollo 11 Command and Service Module name Cape Canaveral, United States
@prefix space: <http://example.com/space-schema/> .
launched 16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass 28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
;
a
http://... space:launchsite <http://.../cape+cana...> .
/Spacecraft
46. http://... launchsite
http://...
/1969-059A /cape+cana...
name Apollo 11 Command and Service Module name Cape Canaveral, United States
@prefix space: <http://example.com/space-schema/> .
launched 16 July 1969
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
<http://example.com/spacecraft/1969-059A>
mass 28801.0 a space:Spacecraft ;
space:name "Apollo 11 Command and Service Module" ;
space:launched "1969-07-16"^^xsd:date ;
space:mass 28801.0 .
;
a
http://... space:launchsite <http://.../cape+cana...> .
/Spacecraft
<http://.../cape+cana...>
space:name "Cape Canaveral, United States"@en-us .
48. SPARQL
Query Language for RDF
http://www.w3.org/TR/rdf-sparql-query
SPARQL Protocol and RDF Query Language
Graph pattern based language
written the same as Turtle
Several queries — Ask; Select; Describe;
Construct
Read Only
still vulnerable to injection, though not as bad as SQL
49. /discipline/
space:Discipline a rdfs:label Space Physics
spacephysics
foaf:name Sputnik 1
space:discipline
dc:description The Sputnik 1 spacecraft was ...
space:agency U.S.S.R
/spacecraft/
space:Spacecraft a
1957-001B
space:mass 86.3
foaf:depiction /images/sputnik.jpg
space:spacecraft
space:launched 1957-10-04
space:Launch a /launch/1957-001
space:launchvehicle Modified SS-6 (Sapwood)
space:launchsite
rdfs:label Tyuratam (Baikonur Cosmodrome)
space:Launchsite a /launchsite/tyurata
space:country U.S.S.R