CODEWITHSUNDEEP
sparqlrdf
user3725561
user3725561

Reputation:

SPARQL query DBLP

I am running this query

SELECT *
WHERE
{
?s dc:creator ?name .
?s rdf:type swrc:Article .
FILTER regex(str(?name), "Jeffrey", "D.", "Ullman") .
}

and I am getting an error of:

Encountered " "," ", "" at line 16, column 41.
Was expecting one of:
    <LANGTAG> ...
    <INTEGER_POSITIVE> ...
    <DECIMAL_POSITIVE> ...

What is the matter with that, am I not conforming with the guidelines? I've searched a bit around and I found the same syntax in various posts.

EDIT:

when I am asking for

SELECT * WHERE { ?s rdf:type swrc:Article . ?s dc:creator ?name . }

I get back: s name <http://dblp.l3s.de/d2r/resource/publications/conf/www/BeszteriV07> [http] <http://dblp.l3s.de/d2r/resource/authors/Istvan_Beszteri> [http] in a single line where the fist URI is the ?s and the second the ?name.

Now I know for a fact that there is an author named "Jeffrey D. Ullman" and I query for:

SELECT * WHERE { ?s rdf:type swrc:Article . ?s dc:creator ?name . FILTER regex(str(?name), "Jeffrey") } LIMIT 10.

I then get back for example: s name <http://dblp.l3s.de/d2r/resource/publications/conf/www/LimWPVA07> [http] <http://dblp.l3s.de/d2r/resource/authors/Jeffrey_Scott_Vitter> [http]

So the question here is how will I be able to match "Jeffrey D. Ullman" and see all the Articles he has written.?

Upvotes: 3

Views: 449

Answers (2)

chrisis
chrisis

Reputation: 1993

Your regex function syntax is incorrect see SPARQL1.1 spec. Note that regex takes exactly two or three arguments, the first being the text, the second the pattern, and the final an optional string containing flags.

17.4.3.14 REGEX

xsd:boolean  REGEX (string literal text, simple literal pattern) 
xsd:boolean  REGEX (string literal text, simple literal pattern, simple literal flags)

Upvotes: 5

scotthenninger
scotthenninger

Reputation: 4001

Some background research on SPARQL is a very good idea. Just to point out the exact problem here, regex matches a string against a regular expression. So the following:

FILTER regex(str(?name), "Jeffrey D\\. Ullman") .

...will match "Jeffrey D. Ullman". The following:

FILTER regex(str(?name), "Ullman") .

...will match "Jeffrey D. Ullman" and anything with "Ullman" in ?name. This filter:

FILTER regex(str(?name), "Ullman$") .

...will match any string ending with "Ullman". And this filter:

FILTER regex(str(?name), "^Jeffrey.*Ullman$") .

...will match any string starting with "Jeffrey", ending with "Ullman", with any character in between.

And so on...

Upvotes: 4

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