| Last verification: | 20180914 |
|---|---|
| Tools required for this lab: | – |
Video [minimum!]:
Reading:
During this lab we will use two services to execute SPARQL queries:
)http://www.daml.org/2003/01/periodictable/PeriodicTable.owl into „Target graph URI (or use FROM in the query)” field and select text output option.http://krzysztof.kutt.pl/didactics/semweb/PeriodicTable.owlGet Results):PREFIX table: <http://www.daml.org/2003/01/periodictable/PeriodicTable#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT ?element ?name
WHERE {
?element table:group ?group .
?group table:name "Noble gas"^^xsd:string .
?element table:name ?name .
}
PREFIX table: <http://www.daml.org/2003/01/periodictable/PeriodicTable#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdfs: <http://w3.org/2000/01/rdf-schema#>
CONSTRUCT {
?element rdfs:label ?name .
}
WHERE {
?element table:group ?group .
?group table:name "Noble gas"^^xsd:string .
?element table:name ?name .
}
What do SELECT queries do? What do CONSTRUCT queries do? :Hydrogen :standardState :gas .
:Hydrogen :standardState what? . :gas?what :standardState :gas . :Hydrogen:Hydrogen ?what :gas . :standardStateperiod_7 periodperiod_7 period and have OPTIONAL color (some of them does not have color!)period_7 period and have OPTIONAL color, sorted by name descending Put the constructed queries in the report. Put the queries in the report.http://dbpedia.org/sparql.rdfs:label property. Maybe this will help us? Let's try!?country) that probably has a relation rdfs:label with object „Polska”@pl. This can be easily translated into SPARQL WHERE clause: ?country rdfs:label "Polska"@pl .
http://dbpedia.org/sparql URI in the dropdown list at the top.PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?country
WHERE {
?country rdfs:label "Polska"@pl .
}
rdfs:label „Polska”@pl! Now expand this query to find information about Poland population and put the final query in the report.-------------- | population | ============== | 38483957 | --------------
Prepare a query that returns a list of 10 countries in Europe with the biggest population. Put the query in the report.------------------------------------------------ | voivodeship | counties | ================================================ | "Masovian Voivodeship"@en | 15 | | "Greater Poland Voivodeship"@en | 12 | | "Lesser Poland Voivodeship"@en | 11 | | "Podkarpackie Voivodeship"@en | 10 | | "Pomeranian Voivodeship"@en | 9 | | "Warmian-Masurian Voivodeship"@en | 9 | | "West Pomeranian Voivodeship"@en | 9 | | "Opole Voivodeship"@en | 8 | ------------------------------------------------
or in Polish:
-------------------------------------------------- | wojewodztwo | powiaty | ================================================== | "Województwo mazowieckie"@pl | 15 | | "Województwo wielkopolskie"@pl | 12 | | "Województwo małopolskie"@pl | 11 | | "Województwo podkarpackie"@pl | 10 | | "Województwo pomorskie"@pl | 9 | | "Województwo warmińsko-mazurskie"@pl | 9 | | "Województwo zachodniopomorskie"@pl | 9 | | "Województwo opolskie"@pl | 8 | --------------------------------------------------
http://dbpedia.org/resource/Powiathttp://dbpedia.org/resource/Voivodeships_of_Poland Put the query in the report.is_father_of or is_child_of or maybe both of them?is_father_of. Now, you can execute CONSTRUCT query that creates inverse relation: PREFIX bb: <http://yourname/b-and-b#>.
CONSTRUCT {
?child bb:is_child_of ?father .
}
WHERE {
?father bb:is_father_of ?child
}
is_uncle_of relation will be useful? No problem! PREFIX bb: <http://yourname/b-and-b#>.
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
CONSTRUCT {
?uncle bb:is_uncle_of ?child .
}
WHERE {
?uncle bb:is_sibling_of ?parent;
a bb:Man.
?child bb:is_child_of ?parent
}
is_sibling_of but instead you have is_sister_of and is_brother_of. Simply prepare query (or queries) that creates is_sibling_of for you. Put this query in the report.www.dropbox.com part of the shared link to dl.dropboxusercontent.com What 3 rules you will find useful in your model from previous lab. Put 3 CONSTRUCT queries in the report.SPARQL also provides two more query types: ASK and DESCRIBE.
PREFIX table: <http://www.daml.org/2003/01/periodictable/PeriodicTable#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
ASK {
?element table:name "aluminium"^^xsd:string .
}
If you run this query against Periodic Table, answer will be yes.
Prepare query that checks something interesting in your model :)MusicCD and was published by Warner Music Group (if you don't have such classes in your library, use analogous class that you have).DESCRIBE <http://www.daml.org/2003/01/periodictable/PeriodicTable#H>
(it should be executed against http://www.daml.org/2003/01/periodictable/PeriodicTable.owl file)
Prepare query that describes all foaf:Person items from your model (if you don't have a foaf:Person class in your library, use analogous class that you have).SELECT ?actor
WHERE {?actor :playedIn :ReturnOfTheJedi .
NOT EXISTS {?actor :diedOn ?deathdate . }
}
SELECT actor_name
FROM movies
WHERE title = "Return of the Jedi"
AND NOT EXISTS (SELECT *
FROM deaths
WHERE movies.actor_name = deaths.name);
What are Open World Assumption (OWA) and Close World Assumption (CWA)? What is the difference between these two queries (refer to the knowledge of OWA and CWA)?If you are interested in querying the huge amount of data available in Wikipedia, there are two projects you may be interested in:
They overlap in part, but are independent of each other and have different uses. For you, a student of the Semantic Web Technologies course, it does not matter much. They are simply large knowledge bases with which you can do a lot of things.
If you want to dive into this data you can start with a Big set of SPARQL queries against Wikidata.
SPARQL:
Sample queries in SPARQL:
Tools:
Open Data Sets:
DB2RDF (RDF and Relational Databases):
