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Questions tagged [r2rml]

R2RML is a language for expressing customized mappings from relational databases to RDF datasets.

R2RML is a language for expressing customized mappings from relational databases to RDF datasets.

An R2RML mapping refers to logical tables to retrieve data from the input database. A logical table can be one of the following:

  • A base table,
  • a view, or
  • a valid SQL query (called an “R2RML view” because it emulates a SQL view without modifying the database).

Each logical table is mapped to RDF using a triples map. The triples map is a rule that maps each row in the logical table to a number of RDF triples.

The rule has two main parts:

  1. A subject map that generates the subject of all RDF triples that will be generated from a logical table row. The subjects often are IRIs that are generated from the primary key column(s) of the table.
  2. Multiple predicate-object maps that in turn consist of predicate maps and object maps (or referencing object maps).

Triples are produced by combining the subject map with a predicate map and object map, and applying these three to each logical table row.

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Apche JENA's integration with data virtualization tools

Anybody did any implementation of Apache JENA on top of RDF models(using R2RML mapping) created from Virtual Databases in Data Virtualization layer. I am specifically looking for integration with JBOSS-Teiid, Apache JENA, R2RML mapping. Any…
shakti prasad mohapatra
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main class exception when running db2triples for the first time

I'm trying to use db2triples for the first time, which is a java / maven project. I got information about it from its github page. So far, I have performed the following steps: cd /programs/db2triples-master vim pom.xml and added the db2triples…
Kristian
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Virtuoso R2RML rr:IRI generating

I have a problem with generating rr:termType rr:IRI in Virtuoso. I don't know if am I doing it wrong but I followed the W3C specification. My mapping looks like this. When I generate triples with CONSTRUCT statement I still get "URL" but not IRI =>…
Buteo Mausjäger
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How make org.openrdf.rio parser supports Turtle documents?

I have a java project on Eclipse that read R2RML (.ttl) file. I am using R2RMLReader from it.unibz.inf.ontop.r2rml.R2RMLReader which uses Open RDF Rio org.openrdf.rio.Rio, here is the method code: public static ArrayList readR2RMLFile()…
نظام الارشاد الطلابي
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JDBC dateformat not allowing zero values in date

I have a SQL dataset with birthdate and deathdate of authors where the date sometimes contains zero values in the month and day area (example: 1947-00-00), this is done when the exact date of the birth or death is not known. I am using R2RML to map…
Emma Sofie Sovik
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Working with RML mapping's split function

I am trying to create a mapping in which I split the full name into a first name and last name using fno in rml. My code is like <#FunctionSplitName> fnml:functionValue [ rml:logicalSource <#LogicalSource>; …
Bahar
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RML Mapping - How to map a restriction?

I am stuck on the mapping of an owl:Restriction and trying to figure out how that could be done using the RML Mapper. The result should be: prefix ns: . ns:SomeResource rdf:type owl:NamedIndividual , [ rdf:type…
airkangoo
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Filling up RDF data from a relational database

I am creating an ontology based on a relational database. Some classes in my ontology are correspondent to some tables in the relational database (PostgreSQL). I already read some documents about mappings from the W3C website. Especially this one…
Pedro Silva
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Processing R2RML mappings in Virtuoso

I have a R2RML mapping file generated with the OnTop Protege Plugin. My purpose is to use these mappings in order to replicate my relational Database in RDF format. Then I want to upload this RDF file into an existing Virtuoso Server. I am aware…
User 23
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D2RQ how to configue many to many relationship

I have a database tables and I'm changing the data to RDF. So far I am able to do the one to one in which a row that has a primary key, has a value, which comes from a column in that row, like this: map:Artist a d2rq:ClassMap; d2rq:dataStorage…
Ania David
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Virtuoso R2RML rr:IRI generating as Literal

I have a problem when generating rr:termType rr:IRI in Virtuoso. When I run the mapping, the result is a Literal instead an IRI. Is this something Virtuoso doesn't support?
Lucas Bassetti
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Virtuoso Dump graph

Hello I have a probably simple problem but I am not able to find it anywhere in docs. I use this code in Virtuoso Interactive SQL: SPARQL clear graph ; SPARQL clear graph…
Buteo Mausjäger
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SPARQL equivalent of a SQL select query?

If I have a SQL table that can be queried like this: Select empname from mytable Where empid=1; What would an equivalent SPARQL query be?
user8112786
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