ONTOLOGY ENGINEERING Lab #6 – October 6, 2014

The FILTER Keyword  Up to this point we’ve restricted the result set of a query by binding a variable to a resource using some object property. For example, the second statement of the following where clause “filters” the result set to roadways in Niagara County: SELECT ?route WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties. } LIMIT 100

The FILTER Keyword  The FILTER keyword enables filtering on string and numeric values. The following SELECT query returns roadways that have “bridge” somewhere in the english label. SELECT ?route ?label WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route rdfs:label ?label. FILTER regex(?label, "bridge", "i"). FILTER (lang(?label)= "en"). } LIMIT 100

The FILTER Keyword  The following SELECT query returns roadways that have lengths greater than 1000 miles. SELECT ?route ?length WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:lengthMi ?length. FILTER (?length > 1000) } LIMIT 100

The FILTER Keyword  The following SELECT query returns public universities located in latitudes between 42 and 43 degrees and in longitudes between -79 and -77 degrees. SELECT ?route ?latitude ?longitude WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route geo:lat ?latitude. ?route geo:long ?longitude. FILTER (?latitude > 42 && ?latitude < 43). FILTER (?longitude > -79 && ?longitude < -77). } LIMIT 100

The FILTER Keyword  The following SELECT query returns public companies that have revenues of more than 1 billion (US dollars) or equity of more than 100 billion (US dollars) SELECT ?company ?int_revenue ?int_equity WHERE { ?company dbpedia-owl:type dbpedia:Public_company. ?company dbpedia-owl:revenue ?revenue. ?company dbpedia-owl:equity ?equity. FILTER (datatype(?revenue) = ). BIND(xsd:integer(?revenue) as ?int_revenue). BIND(xsd:integer(?equity) as ?int_equity). FILTER (?int_revenue > || ?int_equity > ) } LIMIT 100

The Filter Keyword  The following SELECT query uses the FILTER keyword, logical operator ! and the bound function to return roadways that do not have an associated name of their county SELECT ?route ?county WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. OPTIONAL {?route dbpprop:counties ?county }. FILTER(!bound(?county)). } LIMIT 100

The UNION Keyword  Allows you to join multiple queries and return all of the result sets  The following query returns roadways located in Niagara or Orleans counties: SELECT ?route WHERE { { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties. } UNION { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties. } 8

The UNION Keyword  The part of a union query that is common can be written just once: SELECT ?route WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. {?route dbpprop:counties.} UNION {?route dbpprop:counties.} } 9

GROUP BY Keyword  Allows grouping of data together into sets on which aggregate functions can be performed  The following query returns the total length roadways by US state: SELECT ?state (SUM(?length) AS ?totalroadways) WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties ?county. ?county dbpedia-owl:state ?state. ?route dbpprop:lengthMi ?length. } GROUP BY ?state ORDER BY DESC(?totalroadways) 10

GROUP BY Keyword  Other functions available for use include AVG(), MIN(), MAX(), and COUNT()  The following query returns the average length of roadways by US state: SELECT ?state (AVG(?length) AS ?avgroadways) WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties ?county. ?county dbpedia-owl:state ?state. ?route dbpprop:lengthMi ?length. } GROUP BY ?state ORDER BY DESC(?avgroadways) 11

HAVING Keyword  Works for aggregate values in the same way as the FILTER keyword works for individual values  The following query returns states having more than 70,000 miles in roadways: SELECT ?state (SUM(?length) AS ?totalroadways) WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties ?county. ?county dbpedia-owl:state ?state. ?route dbpprop:lengthMi ?length. } GROUP BY ?state HAVING (SUM(?length) > 70000) ORDER BY DESC(?totalroadways) 12

Mathematical Functions  Allow individual values to be added, subtracted, multiplied and divided to return calculated values  The following query returns the area per mile ratio for states in the United States SELECT ?state (?area /(SUM(?length) as ?totallength) as ?areapermile) WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties ?county. ?county dbpedia-owl:state ?state. ?route dbpprop:lengthMi ?length. ?state dbpedia-owl:areaTotal ?area. } ORDER BY DESC(?areapermile) 13

Building a Top Ten List of Area to Length Ratios SELECT ?state (?area /(SUM(?length) as ?totallength) as ?areapermile) WHERE { ?route rdf:type dbpedia-owl:RouteOfTransportation. ?route dbpprop:counties ?county. ?county dbpedia-owl:state ?state. ?route dbpprop:lengthMi ?length. ?state dbpedia-owl:areaTotal ?area. } ORDER BY DESC(?areapermile) LIMIT 10 14

Exercises  Find the number of roadways in counties of New York State  Find the roadways that have a mention of “Buffalo” somewhere in the english version of their abstract  Find roadways that are located in (dbpedia- owl:location) either Toronto or Edmonton  Find roadways that are located in counties that have a population (dbpedia-owl:populationTotal) greater than 1.5 million