Hi Norbert, MarkLogic does not support:
- 14 Basic Federated Query - SPARQL 1.1 Service Description - SPARQL 1.1 Federated Query That is with pure SPARQL. MarkLogic allows wrapping SPARQL statements in XQuery or SJS code that effectively allow mimicking federated search, and the same technique could also be applied outside of MarkLogic as suggested by Erik. Whether Federated search will be added to MarkLogic depends on customer needs, as always, but I’d expect it to be not very likely. As Erik tried to say, MarkLogic is a transactional database, and because of that we cannot rely on 3rd party sparql services. It would be more likely that external linked data sources are loaded into MarkLogic to be queried with MarkLogic. Cheers, Geert From: <[email protected]<mailto:[email protected]>> on behalf of "Weissenberg, Norbert" <[email protected]<mailto:[email protected]>> Reply-To: MarkLogic Developer Discussion <[email protected]<mailto:[email protected]>> Date: Tuesday, August 22, 2017 at 10:12 AM To: MarkLogic Developer Discussion <[email protected]<mailto:[email protected]>> Subject: Re: [MarkLogic Dev General] SPARQL 'SERVICE' ? Hi Eric, as defined in https://www.w3.org/TR/sparql11-query/, SPARQL 1.1 is defined by “eleven SPARQL 1.1 Recommendations produced by the SPARQL Working Group<http://www.w3.org/2001/sw/DataAccess/>: 1. SPARQL 1.1 Overview<http://www.w3.org/TR/2013/REC-sparql11-overview-20130321> 2. SPARQL 1.1 Query Language<http://www.w3.org/TR/2013/REC-sparql11-query-20130321> (this document) 3. SPARQL 1.1 Update<http://www.w3.org/TR/2013/REC-sparql11-update-20130321> 4. SPARQL1.1 Service Description<http://www.w3.org/TR/2013/REC-sparql11-service-description-20130321> 5. SPARQL 1.1 Federated Query<http://www.w3.org/TR/2013/REC-sparql11-federated-query-20130321> 6. SPARQL 1.1 Query Results JSON Format<http://www.w3.org/TR/2013/REC-sparql11-results-json-20130321> 7. SPARQL 1.1 Query Results CSV and TSV Formats<http://www.w3.org/TR/2013/REC-sparql11-results-csv-tsv-20130321> 8. SPARQL Query Results XML Format (Second Edition)<http://www.w3.org/TR/2013/REC-rdf-sparql-XMLres-20130321> 9. SPARQL 1.1 Entailment Regimes<http://www.w3.org/TR/2013/REC-sparql11-entailment-20130321> 10. SPARQL 1.1 Protocol<http://www.w3.org/TR/2013/REC-sparql11-protocol-20130321> 11. SPARQL 1.1 Graph Store HTTP Protocol<http://www.w3.org/TR/2013/REC-sparql11-http-rdf-update-20130321> “ Which of them are not implemented by MarkLogic 9? A first one is Federated Query. But document https://www.w3.org/TR/sparql11-query/ also defines in Chapter 14: “14 Basic Federated Query This document incorporates the syntax for SPARQL federation extensions. This feature is defined in the document SPARQL 1.1 Federated Query<http://www.w3.org/TR/sparql11-federated-query/>. ” Will Federated Query be implemented by MarkLogic in future? Although there are risks as you mentioned, I think it is important for semantic data integration (e.g. for linked open data). Thanks, Norbert Von: [email protected]<mailto:[email protected]> [mailto:[email protected]] Im Auftrag von Erik Hennum Gesendet: Mittwoch, 26. Juli 2017 15:27 An: MarkLogic Developer Discussion <[email protected]<mailto:[email protected]>> Betreff: Re: [MarkLogic Dev General] SPARQL 'SERVICE' ? Hi, Tony: SPARQL SERVICE is an extension to SPARQL 1.1 for federated query: "The SERVICE keyword instructs a federated query processor to invoke a portion of a SPARQL query against a remote SPARQL endpoint." https://www.w3.org/TR/2013/REC-sparql11-federated-query-20130321/#service As an extension, SERVICE is not part of core SPARQL 1.1 Federated queries are at risk for fundamental architecture issues with respect to performance, transactional consistency, resilience, and so on. For that reason, MarkLogic does not federate queries across other data sources. It should be possible to use MarkLogic as one data source for a SPARQL/RDF tool that implements federation. Erik Hennum ________________________________ From:[email protected]<mailto:[email protected]>[[email protected]<mailto:[email protected]>] on behalf of Tony Greaves [[email protected]<mailto:[email protected]>] Sent: Tuesday, July 25, 2017 4:29 PM To: [email protected]<mailto:[email protected]> Subject: [MarkLogic Dev General] SPARQL 'SERVICE' ? The MarkLogic documentation states "SPARQL queries are executed natively in MarkLogic to query either in-memory triples or triples stored in a database. When querying triples stored in a database, SPARQL queries execute entirely against the triple index". This would appear to imply that the SPARQL *SERVICE* function is not supported. Experimentation seems to confirm this, but I have not found any explicit comment to this effect in the documentation. Can someone confirm this one way or the other please? thanks Tony Attention: The information in this email and in any attachments is confidential. If you are not the intended recipient then please do not distribute, copy or use this information. Please notify us immediately and then delete the message from your computer. Any views or opinions presented are solely those of the author.
_______________________________________________ General mailing list [email protected] Manage your subscription at: http://developer.marklogic.com/mailman/listinfo/general
