r2rml

SPARQL equivalent of a SQL select query?

由 这一生的挚爱 提交于 2019-12-13 09:52:41
问题 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? 回答1: As a few people have mentioned here and on your similar, previous question, you probably need to do some more reading about the nature of RDF-modeled data. For Stack Overflow, you definitely need to get into the habit of showing your input data and whatever code you have written so far , even if it isn't working perfectly. In that case, you need to

Virtuoso R2RML rr:IRI generating

由 ↘锁芯ラ 提交于 2019-12-11 11:37:04
问题 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 => <url> ( OWNER_LINK and BRAND_LINK columns). Is it something Virtuoso doesn't support or am I coding it the wrong way? DB.DBA.TTLP ( ' @prefix rr: <http://www.w3.org/ns/r2rml#> . @prefix foaf: <http://xmlns.com/foaf/0.1/> . @prefix gr: <http://purl

What are the pros and cons of RDB2RDF tools? [closed]

由 北战南征 提交于 2019-12-04 02:56:09
问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed last year . I need to know the difference between RDB2RDF tools. Could anybody tell me what are the pros and cons of RDB2RDF tools? Especially for the following ones: Virtuoso, Ultrawrap, Ontop, Morph, Xsparql, D2RQ,.... 回答1: There are two W3C-standardized ways to convert relational data to RDF

What are the pros and cons of RDB2RDF tools? [closed]

由 偶尔善良 提交于 2019-12-01 14:52:28
I need to know the difference between RDB2RDF tools. Could anybody tell me what are the pros and cons of RDB2RDF tools? Especially for the following ones: Virtuoso, Ultrawrap, Ontop, Morph, Xsparql, D2RQ,.... There are two W3C-standardized ways to convert relational data to RDF: Direct Mapping — non-customizable default mapping. Direct Mapping is suitable when relational data is well normalized, there are primary keys, foreign keys etc. R2RML — customizable mapping. In the survey below, I consider R2RML implementations only. Many R2RML implementations are listed here . I do not consider tools

Is there a Java open source implementation of R2RML?

由 ぐ巨炮叔叔 提交于 2019-11-30 19:05:49
I want to generate RDF data from tabular data, in particular: CSV, TSV, spreadsheets (either Excel or OpenOffice) and, eventually, tables in RDBMS. I am aware of the "RDB to RDF Mapping Language" (R2RML) (http://www.w3.org/TR/r2rml/) current draft. I use Apache Jena for processing, storing and querying RDF data and/or reading CSV or TSV files. I use Apache POI for reading Microsoft Excel spreadsheets and I am planning to use Apache ODF Toolkit for reading OpenOffice spreadsheets. Is there a Java open source (preferably ASL) implementation of R2RML I can use? D2RQ is the underling

Is there a Java open source implementation of R2RML?

由 我与影子孤独终老i 提交于 2019-11-30 03:36:56
问题 I want to generate RDF data from tabular data, in particular: CSV, TSV, spreadsheets (either Excel or OpenOffice) and, eventually, tables in RDBMS. I am aware of the "RDB to RDF Mapping Language" (R2RML) (http://www.w3.org/TR/r2rml/) current draft. I use Apache Jena for processing, storing and querying RDF data and/or reading CSV or TSV files. I use Apache POI for reading Microsoft Excel spreadsheets and I am planning to use Apache ODF Toolkit for reading OpenOffice spreadsheets. Is there a
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