Questions tagged [virtuoso]
Virtuoso is a multi-model relational database management system for data represented as Relational Tables and/or RDF Property Graphs. It is also equipped with in-built middleware for conceptual data integration across heterogeneously shaped and disparately located data.
virtuoso
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SPARQL Encapsulated `OPTIONAL` in complex query
I have a SPARQL query that uses several OPTIONAL, some inside the others, as well as UNIONs. I had heard that those are the ingredients for trouble but didn't have problem until now, and I can't ...
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How to achieve compliance between Graphql in Virtuoso and Python graphql-db-api
Recent additions of GraphQL views to Open Link Virtuoso motivated to make one more attempt of using data from Virtuoso in Apache Superset.
For that purpose, Python lib graphql-db-api may be used. It ...
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How to query Virtuoso SPARQL endpoint from Python with user-specific credentials to test performance based on graph permissions? [duplicate]
I am running Virtuoso on a Docker container on localhost:8890. My goal is to test whether adding permissions/restrictions to certain graphs results in time inefficiencies when querying. For this ...
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Weird behavior on LIMIT and OFFSET when querying DBPedia
I'm querying DBPedia's Virtuoso endpoint via RDFLib in order to get all entities of type dbo:Politician with no other occupation than that, and I have noticed that the results I get when performing ...
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Jena 4 connection to Virtuoso
How can I access authenticated Virtuoso OpenSource SPARQL 1.1. graph store protocol through Jena 4? I am facing this problem after having upgraded my codebase from Jena 3 (Apache HttpClient) to Jena 4 ...
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How to avoid inconsistency with syntax of OpenLink Virtuoso SQL in Apache Superset
In Apache Superset if OpenLink Virtuoso database is used (ODBC driver + Alchemy dialect), the following error is displayed for any SQL query:
That's because Apache Superset automatically adds LIMIT ...
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46
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Blank nodes vs variables in SPARQL queries
These two SPARQL queries result in different returns in this SPARQL endpoint (Swedish libraries). Why? I expected them to be functionally equivalent.
Query 1
PREFIX : <https://id.kb.se/vocab/>
...
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Prisma ORM as SPARQL client in semantic web
if we add linked data representation in Prisma ORM schemas properly, is it possible to achieve SPARQL functions as with Virtuoso database?
I am using nextJS with Prisma ORM for linked data ...
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How to set default SQL options for all SQL queries in OpenLink Virtuoso
Currently I actively exploit a very attractive ability of Virtuoso to define SQL views using SPARQL. When I use these views in a composite SQL query without any Virtuoso-specific options,
the ...
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How can I open a lef file use virtuoso
I want to see what a lef file describe, but it seems virtuoso can't open the lef file directly. Do we have some way to open lef file?
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Virtuoso 42000 Error D1CTX after using curl to retrieve RDF data from dbpedia.org
I am a new user to the technical world of semantic web, RDF and data retrieval using curl. I am trying to use curl from macOS Terminal.app (macOS Ventura 13.3) to retrieve RDF data in XML format from &...
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Get weighted shortest path in an Openlink Virtuoso Knowledge Graph
Context
Given a certain KG with the following structure
<distanceTo:1> <weight> 3 .
<distanceTo:1> <weight> 4 .
<a> ...
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Virtuoso bulk insert failed
I'm using Windows 11 and I was trying to make a bulk insert with OpenLink Virtuoso Open Source edition. I was following this guide: https://docs.openlinksw.com/virtuoso/fn_ld_dir_all/.
I updated the ...
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Combining Apache Jena with OpenLink Virtuoso in Springboot
I'm using SpringBoot to develop an application combining Apache Jena with an OpenLink Virtuoso Service instance. Checking this guide OpenLink Documentation, I'm moving as follows:
Set the pom (...
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How does SPARQL queries automatically read namespaces for abbreviations in virtuoso?
I've set up some namespaces in virtuoso, but when I used jena to do sparql queries in virtuoso, some namespaces were not abbreviated:
@prefix sio: http://semanticscience.org/resource/SIO_ .
@...
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