How to filter distinct regex matches with SPARQL? - sparql

I am querying a (kind of) bibliographic database and would like to find all the distinct matches of a certain regex (matching the signature of typescripts (TS) and manuscripts (MS)); i.e. I would like to return all documents that are currently in the database.
I came up with
SELECT ?document
WHERE
{
{
?documentURI a witt:MS;
rdfs:label ?document.
}
UNION
{
?documentURI a witt:TS;
rdfs:label ?document.
}
FILTER (regex(?document, "(Ms|Ts)\\-((1|2|3)\\d{2}\\w?\\d?)"))
}
(endpoint); this returns all the signatures but I would like to filter the result for the distinct regex matches, i.e. the distinct signatures up to and excluding the comma.
How can this be achieved?


Ok, I think I found a solution with strbefore:
SELECT DISTINCT ?document
WHERE
{
{
?documentURI a witt:MS;
rdfs:label ?documentFull.
}
UNION
{
?documentURI a witt:TS;
rdfs:label ?documentFull.
}
BIND (strbefore(?documentFull, ",") AS ?document)
}
Try it.
Would appreciate opinions on the query though, is this effective/good style?

Related

Filter by predicate attributes

How can I get all chairpersons, which are still holding this job (where the predicate has no end date?).
My current version returns all chairpersons:
SELECT ?chairperson ?x WHERE {
?university wdt:P488 ?chairperson.
}

How to simulate or change the GROUP BY in an SPARQL Query?

I have executed successfully this query in D2RQ, but, since performance problems I'm using now Ontop which performs faster but it does not support aggregated functions like GROUP BY, which in the case of this query is key to get the desired results.
Any idea how can I do a similar query without using the GROUP BY?
PREFIX d2r: <http://sites.wiwiss.fu-berlin.de/suhl/bizer/d2r-server/config.rdf#>
PREFIX v: <http://www.vocab.com/resource/vocab/>
SELECT ?hour ((?latest - ?earliest) as ?value) {
{
SELECT ?hour (MIN(?value) as ?earliest) WHERE {
?s v:time ?time;
v:value ?value
}
GROUP BY (HOURS(?time) as ?hour)
}
{ SELECT ?hour (MAX(?value) as ?latest) WHERE {
?s v:time ?time;
v:value ?value
}
GROUP BY (HOURS(?time) as ?hour)
}
FILTER (?hour>= timeFrom && ?hour <= timeTo)
}
ORDER BY ?hour

Searching semantically tagged documents in MarkLogic

Can any one please point me to some simple examples of semantic tagging and querying semantically tagged documents in MarkLogic?
I am fairly new in this area,so some beginner level examples will do.

When you say "semantically tagged" do you mean regular XML documents that happen to have some triples in them? The discussion and examples at http://docs.marklogic.com/guide/semantics/embedded are pretty good for that.
Start by enabling the triple index in your database. Then insert a test doc. This is just XML, but the sem:triple element represents a semantic fact.
xdmp:document-insert(
'test.xml',
<test>
<source>AP Newswire</source>
<sem:triple date="1972-02-21" confidence="100">
<sem:subject>http://example.org/news/Nixon</sem:subject>
<sem:predicate>http://example.org/wentTo</sem:predicate>
<sem:object>China</sem:object>
</sem:triple>
</test>)
Then query it. The example query is pretty complicated. To understand what's going on I'd insert variations on that sample document, using different URIs instead of just test.xml, and see how the various query terms match up. Try using just the SPARQL component, without the extra cts query. Try cts:search with no SPARQL, just the cts:query.
xquery version "1.0-ml";
import module namespace sem = "http://marklogic.com/semantics"
at "/MarkLogic/semantics.xqy";
sem:sparql('
SELECT ?country
WHERE {
<http://example.org/news/Nixon> <http://example.org/wentTo> ?country
}
',
(),
(),
cts:and-query((
cts:path-range-query( "//sem:triple/#confidence", ">", 80) ,
cts:path-range-query( "//sem:triple/#date", "<", xs:date("1974-01-01")),
cts:or-query((
cts:element-value-query( xs:QName("source"), "AP Newswire"),
cts:element-value-query( xs:QName("source"), "BBC"))))))

In case you are talking about enriching your content using semantic technology, that is not directly provided by MarkLogic.
You can enrich your content externally, for instance by calling a public service like the one provided by OpenCalais, and then insert the enrichments to the content before insert.
You can also build lists of lookup values, and then using cts:highlight to mark such terms within your content. That could be as simple as:
let $labels := ("MarkLogic", "StackOverflow")
return
cts:highlight($doc, cts:word-query($labels), <b>{$cts:text}</b>)
Or with a more dynamic replacement using spraql:
let $labels := map:new()
let $_ :=
for $result in sem:sparql('
PREFIX demo: <http://www.marklogic.com/ontologies/demo#>
SELECT DISTINCT ?label
WHERE {
?s a demo:person.
{
?s demo:fullName ?label
} UNION {
?s demo:initialsName ?label
} UNION {
?s demo:email ?label
}
}
')
return
map:put($labels, map:get($result, 'label'), 'person')
return
cts:highlight($doc, cts:word-query(map:keys($labels)),
let $result := sem:sparql(concat('
PREFIX demo: <http://www.marklogic.com/ontologies/demo#>
SELECT DISTINCT ?s ?p
{
?s a demo:', map:get($labels, $cts:text), ' .
?s ?p "', $cts:text, '" .
}
'))
return
if (map:contains($labels, $cts:text))
then
element { xs:QName(fn:concat("demo:", map:get($labels, $cts:text))) } {
attribute subject { map:get($result, 's') },
attribute predicate { map:get($result, 'p') },
$cts:text
}
else ()
)
HTH!

ARQ Making a Query from Scratch

I have a problem in building the query from scratch syntactically or in algebra, based on
https://jena.apache.org/documentation/query/manipulating_sparql_using_arq.html
For example I have the below query
SELECT (count(?instance) AS ?count)
WHERE
{ ?instance <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://data.linkedmdb.org/resource/movie/film> }
(project (?count)
(extend ((?count ?.0))
(group () ((?.0 (count ?instance)))
(bgp (triple ?instance <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://data.linkedmdb.org/resource/movie/film>)))))
Can any one direct me with a sample code of how to build the above query from scratch?
I have tried to build it syntactically but failing to know about how to alias the aggregation above.
If anybody can at least guide me in including aggregation with its aliasing name in projection it will be very great.

I don't typically construct queries through code, since I can just parse a query string, or use a parameterized SPARQL query, but here's a reconstruction of your query using the API. Most of the methods I used here I found by exploring the autocomplete options in Eclipse, and by looking at the Javadoc.
import com.hp.hpl.jena.graph.Node;
import com.hp.hpl.jena.graph.Triple;
import com.hp.hpl.jena.query.Query;
import com.hp.hpl.jena.query.QueryFactory;
import com.hp.hpl.jena.sparql.core.Var;
import com.hp.hpl.jena.sparql.expr.ExprAggregator;
import com.hp.hpl.jena.sparql.expr.ExprVar;
import com.hp.hpl.jena.sparql.expr.aggregate.AggCountVar;
import com.hp.hpl.jena.sparql.syntax.ElementTriplesBlock;
import com.hp.hpl.jena.vocabulary.RDF;
public class QueryBuilding {
public static void main(String[] args) {
// Create the query and make it a SELECT query.
final Query query = QueryFactory.create();
query.setQuerySelectType();
// Set the projection expression.
final ExprVar instance = new ExprVar( "instance" );
query.getProject().add( Var.alloc( "count" ), new ExprAggregator( instance.asVar(), new AggCountVar( instance )));
// Construct the triples pattern and add it.
final ElementTriplesBlock triples = new ElementTriplesBlock();
final Node film = Node.createURI( "http://data.linkedmdb.org/resource/movie/film" );
triples.addTriple( new Triple( instance.getAsNode(), RDF.type.asNode(), film ));
query.setQueryPattern( triples );
// Show the query
System.out.println( query );
}
}
The output (i.e., the printed query) follows. It's the same as your query, modulo some whitespace location and newlines.
SELECT (count(?instance) AS ?count)
WHERE
{ ?instance <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://data.linkedmdb.org/resource/movie/film> .}

Although the solution proposed by Joshua was very helpful to me and produces the correct String output, I have found that it contains a problem; the line :
query.getProject().add( Var.alloc( "count" ), new ExprAggregator( instance.asVar(), new AggCountVar( instance )));
Should be replaced by :
query.getProject().add( Var.alloc( "count" ), query.allocAggregate( new AggCountVar( instance ) ));
Otherwise if you execute the query against a Model you will get an exception "NotAVariableException: Node_variable (not a Var) found"

Problem with a select SPARQL query on dbpedia

At http://dbpedia.org/sparql/ I want to select something like this:
SELECT ?hostCity WHERE { <http://dbpedia.org/resource/Lisbon> <http://dbpedia.org/property/hostCity> ?hostCity . }
Do you know, where is a problem?

I solve this problem:SELECT ?hostCity WHERE { ?hostCity <http://dbpedia.org/property/hostCity> <http://dbpedia.org/resource/Lisbon . }