Without a fulltext index SPARQL string matching/containment operations
might need a full scan of the data compared to the efficiency of
datastructures like inverse lists etc. that are used in a fulltext index.

> Yes I understand this, my problem is that I don't understand why/when would I 
> want to use this and when standard STR functions are OK instead.
>
>
>> The fullext index via Lucene is only used if you use the corresponding
>> special predicate (which is non-standard SPARQL syntax) in your query:
>>
>> text:query
>>
>> e.g. in a query like (taken form the documentation):
>>
>> PREFIX text: <http://jena.apache.org/text#>
>> PREFIX rdfs: 
>> <http://www.w3.org/2000/01/rdf-schema#[http://www.w3.org/2000/01/rdf-schema#]>
>>
>> SELECT ?s
>> { ?s text:query (rdfs:label 'word' 10) ;
>> rdfs:label ?label
>> }

-- 
Lorenz Bühmann
AKSW group, University of Leipzig
Group: http://aksw.org - semantic web research center

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