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Questions tagged [arq]

A query engine for Jena that supports the SPARQL RDF Query language

A query engine for Jena that supports the SPARQL RDF Query language.

Features

  • Standard SPARQL
  • Free text search via Lucene
  • SPARQL/Update
  • Access and extension of the SPARQL algebra
  • Support for custom filter functions
  • Property functions for custom processing of semantic relationships
  • Aggregation, GROUP BY and assignment as SPARQL extensions
  • Support for federated query
  • Support for extension to other storage systems
  • Client-support for remote access to any SPARQL endpoint

Documentation

74 questions
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Jena Arq Stage Reordering?

So I know Jena Arq supports stage reordering as an optimization. (See https://github.com/apache/jena/blob/master/jena-arq/src/main/java/org/apache/jena/sparql/engine/main/StageGeneratorGeneric.java) On line #70, there is a check for if the input is…
Mark
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Jena ARQ query execution extension

We are trying to extend jena ARQ by adding a new operator. However, for now, we don't want to do this from the very beginning i.e., going through all steps from the query parse to query execution. We are thinking to rewrite the execution plan…
sgao
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How to use Jena ARQ in Maven?

We are trying to develop an extension for Jena ARQ by adding a new operator. We are wondering how to use jena and/or arq in maven to fulfill this task. We see a number of maven artifacts out there. Can somebody give us a hint or an example which…
sgao
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SPARQL extension function , where is added to SPARQL grammar?

I want to know when i creating sparql extension functions with apache jena arq, where is it added to the grammar sparql, for the property function and filter function.
Hmaida Abdelhedi
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rdf jena api compared subject predicate object

I created a function of extension sparql! how I can compare the subject,object and proopriété of rdf file with the parameter of the function which are (subject, property, object)? This is my function but it does not display any result! import static…
Hmaida Abdelhedi
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How to query multiple tables using ARQ jena?

Overview I am using ARQ in order to query local RDFfiles. The query is applied on 5 files which are: a_m.nt, description.nt, labels.nt, links.nt, literals.nt Information is modeled as a set of triples: subject predicate object Algorithm First I…
Hani Goc
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DBPedia (de) data with JENA: character encoding errors ("not unicode")

I try to acces DBpedia (de) data on my local machine. Having downloaded and unzipped some ttl-Files I tried to test a very simple SPARQL query. PREFIX rdf: PREFIX skos:…
cis
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Does ARQ support SPARQL 1.1 Date and Time Functions?

I have been trying to do some formatting of date/time values to make them display as string literals in the result. I am using Jena ARQ from apache-jena-2.11.0 . PREFIX rdfs: PREFIX prov:…
Interition
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Virtuoso and Jena: Large RDF graphs loading issue

I have a 200GB RDF file in .nt format. I want to load it in Virtuoso (using Virtuoso Open-Source Edition 6.1.6). I used Virtuoso bulk loader from command line but loading gets hang after couple of hours of running. Do you have any idea how I can…
Beautiful Mind
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setting .zshrc for arq jena

I'm trying to set my .zshrc file to export ARQROOT for ARQ (jena) on a mac (mavericks), similar to what is shown on http://jena.sourceforge.net/ARQ/Tutorial/query1.html for windows and linux tried all sorts of combinations with paths, quotes and…
Ricardo Pietrobon
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Jena/arq request without results

I'm writing a semantic web application and I have some problems with Jena. I would like to execute a parametirized query and there is no results. The following code presents my query: public ArrayList getPieceByContrName(String n){ Property pr=…
fadox
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Can I force Jena (ARQ) to execute my query plan?

I am working with Jena (ARQ) and I have generated a new query plan. I am not sure how exactly can I ask Jena to execute my query plan instead of generating its own optimized/reordered query plan. Any kind of help is appreciated. Thanks.
Kashif Rabbani
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Inserting an OntModel instance into a Triple Store (like TDB) using ARQ (SPARQL processor for Jena)

How can I insert an OntModel instance into a Triple Store (like TDB) using ARQ (SPARQL processor for Jena? I have the following code which simply creates books, and add these into an OntModel. Now I want to insert this into a Triple Store: public…
ishmaelMakitla
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How to pass function to arq worker on python

Run arq worker with some function that have some task to do but getting for below one. arq import Worker w = Worker(functions=[], redis_settings=WorkerSettings.redis_settings(), max_jobs=1000, keep_result_forever=True, …
hungry_in_learning
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