1.
SPARQL Query Forms Leigh Dodds, Oxford SWIG, March 2008 Photo Credit: Glen Bowman

2.
Why are there 4 SPARQL Query Forms? SPARQL Use Cases doesn’t help very much…

3.
…neither does the SPARQL specification <ul><li>SELECT </li></ul><ul><li>Returns all, or a subset of, the variables bound in a query pattern match. </li></ul><ul><li>CONSTRUCT </li></ul><ul><li>Returns an RDF graph constructed by substituting variables in a set of triple templates. </li></ul><ul><li>ASK </li></ul><ul><li>Returns a boolean indicating whether a query pattern matches or not. </li></ul><ul><li>DESCRIBE </li></ul><ul><li>Returns an RDF graph that describes the resources found. </li></ul>

4.
What are they for?

5.
SELECT Equivalent to SQL SELECT Returns a nice, regular table

6.
SELECT PREFIX table: <http://www.daml.org/2003/01/periodictable/PeriodicTable#> SELECT ?name ?weight WHERE { ?element table:name ?name; table:atomicWeight ?weight. } ORDER BY DESC(?weight) LIMIT 10

7.
ASK Returns a true/false value Is there data that looks like this ? Do you have any information about that ?

8.
ASK PREFIX foaf: <http://xmlns.com/foaf/0.1/> ASK WHERE { ?person a foaf:Person ; foaf:mbox <mailto:leigh@ldodds.com>. } (SPARQL equivalent of a vanity search!)

9.
CONSTRUCT Returns an RDF graph Extract a specific subset of the queried data I want this , this , and this

10.
CONSTRUCT PREFIX foaf: <http://xmlns.com/foaf/0.1/> CONSTRUCT { ?friend a foaf:Person; foaf:name ?name; foaf:homepage ?home. } WHERE { ?person foaf:mbox <mailto:leigh@ldodds.com>; foaf:knows ?friend. ?friend foaf:name ?name; foaf:homepage ?home. }

11.
DESCRIBE Returns an RDF graph Tell me about this or things that look like this … but you decide what’s relevant

12.
DESCRIBE PREFIX foaf: <http://xmlns.com/foaf/0.1/> DESCRIBE ?friend WHERE { ?person foaf:mbox “mailto:leigh@ldodds.com”; foaf:knows ?friend. }

13.
Applied Uses Beyond the basics

14.
DESCRIBE for Prototyping DESCRIBE <http://example.org/someResource> Quickly assembling UIs Web APIs

15.
SELECT for Indexing Building an ordering over some data ORDER BY, LIMIT

16.
CONSTRUCT for Transformation … and also simple inferencing CONSTRUCT could be the XSLT of RDF Currently limited by lack of expressions in CONSTRUCT triple templates

17.
CONSTRUCT for Transformation PREFIX foaf: <http://xmlns.com/foaf/0.1/> PREFIX ex: <http://www.example.org/blogger/> CONSTRUCT { ?person a ex:Blogger. } WHERE { ?person foaf:weblog ?blog. }

18.
SPARQL for Validation XSLT can be used for XML Validation (Schematron) SPARQL can be used for RDF Validation

19.
Validation – ASK * ASK WHERE { #triple patterns that you don’t want to find } *Source: Talis Platform Field Predicate Map Validation

20.
Validation – CONSTRUCT * CONSTRUCT { #some error message or data } WHERE { #triple patterns that you don’t want to find } *Source: Alistair Miles, Schemarama 2 Jena 2 Validation Support

21.
In Combination?

22.
The ADC Pattern ASK – DESCRIBE – CONSTRUCT Probe endpoint Grab default view of data Refine data extraction and/or apply transformation

23.
Questions?