Re: [Bigdata-developers] TupleQuery vs. ParsedQuery

[Artem K. <art...@gm...>]

Hi Adrian,

Query that you are trying to parse is not a valid SPARQL query - "The
variable introduced by the BIND clause must not have been used in the group
graph pattern up to the point of use in BIND.
" [https://www.w3.org/TR/sparql11-query/#bind] .

Regards,

Artem

On Wed, Jan 11, 2017 at 3:15 PM, Adrian Bielefeldt <
Adr...@ma...> wrote:

> Hello everyone,
>
> I'm writign on behalf of a Wikidata Research Project
> <https://meta.wikimedia.org/wiki/Research:Understanding_Wikidata_Queries>
> into SPARQL-Queries. We are writing a java application to parse
> SPARQL-Queries from the query.wikidata.org-logs and analyse them for
> different features. At the moment we are parsing the queries with
> org.openrdf.query.parser.QueryParserUtil into
> org.openrdf.query.parser.ParsedQuery-Objects. Unfortunatly we cannot
> parse queries like this one:
>
> SELECT DISTINCT ?item
> WHERE
> { ?tree0 wdt:P31 ?item . BIND (wd:Q146 AS ?tree0) }
>
> because of: "BIND clause alias '{}' was previously used".
>
> If we parse them as org.openrdf.query.TupleQuery-Objects using
> org.openrdf.repository.RepositoryConnection.prepareTupleQuery they are
> parsed just fine.
>
> Unfortunatly, the TupleQuery-Objects do not support the analysis-Features
> of ParsedQuery.
>
> All of which leads to 2-3 questions:
>
> 1. Why is this kind of query accepted by one parser but not the other?
> 2. Is it possible to obtain a ParsedQuery-Object from a TupleQuery-Object?
> (3. Is this the right mailing list to post these questions to?)
>
> Greetings,
>
> Adrian Bielefeldt
>
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