Hi Peter,
D2RQ currenty doesn’t translate string functions like REGEX (or SUBSTR which
would be more appropriate here) to SQL. This means it will evaluate the query
by retrieving all names and doing the regex evaluation in Java code. Now, the
DBLP service is apparently run in restricted mode where a LIMIT 10000 is
applied to all SQL queries. These two things taken together lead to incomplete
results here.
Possible solutions:
a) Wait until dblp.l3s.de upgrades to some future version of D2RQ that solves
the above limitation
b) Obtain an RDF dump of the dataset, load it into your own local RDF store,
and run the SPARQL query locally against that.
Best,
Richard
On 10 Apr 2014, at 14:41, Wetz Peter <peter.w...@tuwien.ac.at> wrote:
> Dear all,
>
> as already explained on the public-lod list at the W3C (see [1]), I have a
> problem querying the DBLP SPARQL endpoint at [2]. I want to apply the
> Regex-Filter in order to get only authors who match the Regex. I think this
> is the only way to search for authors, if I want to do some sort of
> string-based search. As I did not get the expected results with my query, I
> found, that the REGEX is only applied to the first 10.000 results, since this
> is obviously the result limit.
>
> Therefore, the following query, which aims at returning authors starting with
> the letter “B”, yields 0 results:
>
> SELECT DISTINCT * WHERE {
> ?a a foaf:Agent .
> ?a foaf:name ?n .
> FILTER regex(?n, '^b', 'i')
> }
> LIMIT 10
>
> Is there any other way to find authors starting with “B”? Am I missing
> something?
>
> Best regards,
> Peter
>
> [1] http://lists.w3.org/Archives/Public/public-lod/2014Apr/0025.html
> [2] http://dblp.l3s.de/d2r/snorql/
>
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