1. Semantic Web Overview Open Data Group 23 rdFeb 2011 @ianibbo
This work is licensed under a Creative Commons Attribution 3.0
Unported License.
2. Overview
Scene Setting
Questions you should be able to answer at the end
Major Aspects & Building Blocks
Conceptual Model and Vision
The (Distributed) Graph Model 3. My ability to describe what I
know 4. Your ability to ask me questions
Details
Descriptions & Descriptive Bindings - RDF
RDFXML, RDFa, n3, turtle, ntriples
Storage 5. Retrieval
SPARQL
6. Scene Setting (1)
Semantic Web
Whats it good for?
Anyone can say anything about anything (And thats a good thing!
(?)) 7. Ability to describe unforeseen classes 8. The real goal
Collect facts from lots of sources 9. 10. Then ask some
questions
11. Scene Setting (2)
Semantic Web (Really Semantic Stores)
Whats it not (so) good for?
Tabular Data actually not so bad 12. Updating Group Operations
on Tabular Data more of an issue 13. Frequent/atomic/isolated
Updates (anecdotally) 14. Transactional Capabilities 15. Modern
Search Capabilities Spatial, Text, other. 16. Identity
Generation
How to know the difference? 17. Coordinationisstill needed This
is not a free-for-all Honest! 18. Provenance of data sets (Resource
provenance good)
A common syntax, to which words can be easily added. 36.
Understood over the internet 37. Descriptions which can be used in
many different ways
38. Details Descriptions & Descriptive Bindings - RDFXML
Rose Bush A Guide to Growing Roses Describes process for planting
and nurturing different kinds of rose bushes.2001-01-20 39. Details
Descriptions & Descriptive Bindings - RDFa
The trouble with Bob Alice ...
Jo's Barbecue Eve ...
40. Details Storage Triple Stores & Quad Stores
Why
Once you have a description in your hand....
Temporary or Permanent 41. Updates / Static 42. Public /
Private 43. Provenance 44. What is a triple/quad store, why is it
special 45. RDF Changesets
46. Details Query Languages & Servers - SPARQL
A SPARQL Query
Prefix declarations, for abbreviating URIs 47. Dataset
definition, stating what RDF graph(s) are being queried 48. A
result clause, identifying what information to return from the
query 49. The query pattern, specifying what to query for in the
underlying dataset 50. Query modifiers, slicing, ordering, and
otherwise rearranging query results
51. Details Query Languages & Servers - SPARQL PREFIX foo:
... # dataset definition FROM ... # result clause SELECT ... #
query pattern WHERE { ... } # query modifiers ORDER BY ... 52.
Details Query Languages & Servers - SPARQL prefix sch-ont:
prefix spatial: SELECT ?name ?district ?postcode ?lat ?long
?openDate ?email ?urbanRural ?ratio WHERE { ?school a
sch-ont:School; sch-ont:establishmentName ?name;
sch-ont:districtAdministrative ?district;
sch-ont:districtAdministrative . OPTIONAL { ?school
sch-ont:openDate ?openDate; } OPTIONAL { ?school spatial:long
?long; } OPTIONAL { ?school spatial:lat ?lat; } OPTIONAL { ?school
sch-ont:SCUpreferredemail ?email; } OPTIONAL { ?school
sch-ont:urbanRural ?urbanRural; } OPTIONAL { ?school
sch-ont:pupilTeacherRatio ?ratio; } } ORDER BY ?name
http://services.data.gov.uk/education/sparql 53. The coolest thing
done with your datawill be done by somebody else. Semantic Web
should make this much less painful for that somebody else 54.
Things not covered
