On 20/10/2011 14:31, Ján Mojžiš wrote:
thanx very much Brian!
I figured it out.
Excellent.
If you could tell me whether it is possible to get COUNT also.
Yes - see http://www.w3.org/TR/sparql11-query/#aggregates
I mean, in
one query with SELECT something.
It doesnt need to be this query, just imaginary query, SELECT something, and
get the count. I want to use it in conjunction with LIMIT. LIMIT to 10 for
instance and get the remaining COUNT (those that were not selected).
I don't know how to do that or if you can do that. You may need two
queries - one to get the first 10 results,
and another to count the total number of results if there are 10 or more.
Hmm - maybe you could express it with two subselects:
SELECT ?some ?all
WHERE {
# count all the results
SELECT COUNT(?all) AS ?totalCount
WHERE {
# select the things you wish to count as ?all
}
# get the first 10
SELECT ?some {
WHERE {
# select the things you wish to count as ?some
} limit 10
}
Essentially you are doing two queries anyway, if this works. Why does
it matter if you two queries or one? Or is this an academic exercise?
Brian
Would like to help, I am thankful.
Jan
2011/10/20 Brian McBride<[email protected]>
So your query is:
[[
SELECT ?name ?title
{
?s dc:title ?title.
?o foaf:name ?name.
?o foaf:name "Donald D. Chamberlin"
}
LIMIT 5
]]
That doesn't do what you think it does, because it does relate ?o to ?s. ?o
can be anything with a foaf:name property of "Donald D. Chamberlin" and
?name will return all the values for the foaf:name property for that
resource - there is only one - "Donald D. Chamberlin".
What you need to do is get a query that will return the other authors of
the publication, e.g.
SELECT ?coauthorName ?title
WHERE {
?author foaf:name "Donald D. Chamberlin" . # put first as its most
restrictive
?publication<editor> ?author . # now select all the publications with that
author as editor
# you didn't provide a namespace for the editor property
?title dc:title ?title # get the title of the publication
?publication<editor> ?coauthor . # now find all the authors of that
publication
FILTER (?coauthor != ?author) # eliminate the original author specified
?coauthor foaf:name ?coauthorName # get the name of the coauthor
# done
}
On 20/10/2011 11:41, Ján Mojžiš wrote:
Hi there,
I have a following-type records:
<rdf:Description
rdf:about="http://www.w3.org/**TR/xquery<http://www.w3.org/TR/xquery>
"><dc:identifier>www/**org/w3/TR/xquery</dc:**
identifier><dc:date>2002-01-**03</dc:date><rdf:type
rdf:resource="http://sw.deri.**org/~aharth/2004/07/dblp/dblp.**owl#Www<http://sw.deri.org/%7Eaharth/2004/07/dblp/dblp.owl#Www>
"/>
<editor><foaf:Person rdf:nodeID="DonaldDChamberlin"**><foaf:name>Donald
D.
Chamberlin</foaf:name></foaf:**Person></editor>
<editor><foaf:Person rdf:nodeID="DanielaFlorescu"><**foaf:name>Daniela
Florescu</foaf:name></foaf:**Person></editor>
<editor><foaf:Person rdf:nodeID="JonathanRobie"><**foaf:name>Jonathan
Robie</foaf:name></foaf:**Person></editor>
<editor><foaf:Person
rdf:nodeID="Jérô**meSiméon"><foaf:name>J&#**xE9;rôme
Siméon</foaf:name></foaf:**Person></editor>
<editor><foaf:Person rdf:nodeID="MugurStefanescu"><**foaf:name>Mugur
Stefanescu</foaf:name></foaf:**Person></editor>
<dc:title rdf:parseType="Literal">**XQuery: A Query Language for
XML</dc:title>
<year>2001</year>
They are books or publications, where each one can have multiple authors
(co-authors).
First I search books based on foaf:person - one author. To get his
publications. My working query is:
PREFIX foaf:<http://xmlns.com/foaf/0.**1/<http://xmlns.com/foaf/0.1/>>
PREFIX
rdf:<http://www.w3.org/1999/**02/22-rdf-syntax-ns#<http://www.w3.org/1999/02/22-rdf-syntax-ns#>>
#type
PREFIX dc:<http://purl.org/dc/**elements/1.1/<http://purl.org/dc/elements/1.1/>>
# identifier, date,
creator, title
SELECT ?name ?title
{
?s dc:title ?title.
?o foaf:name ?name.
?o foaf:name "Donald D. Chamberlin"
}
LIMIT 5
It returns
------------------------------**------------------------------**
------------------------------**------------
| name |
title
==============================**==============================**
==============================**============
| "Donald D. Chamberlin" | "PRPL: A Database Workload Specification
Language, v1.3."^^rdf:XMLLiteral
| "Donald D. Chamberlin" | "Efficient View Maintenance at Data
Warehouses."^^rdf:XMLLiteral
| "Donald D. Chamberlin" | "Self-organizing
Map"^^rdf:XMLLiteral
| "Donald D. Chamberlin" | "Beowulf Project at
CESDIS"^^rdf:XMLLiteral
| "Donald D. Chamberlin" | "The MPEG Home
Page"^^rdf:XMLLiteral
------------------------------**------------------------------**
------------------------------**------------
But also I want co-authors of each found match! NOW how to get co-authors?
I
have spent many hours trying to get co-authors in single query, with no
success.
Please be so kind to help.
Many thanks
Jan
