Bassam, I think I came on a little strong. While I’m an IT practitioner in this field, I’m not a researcher. You are doing research. NLM’s MeSH RDF Pilot, like other federal IT projects, has to be careful about security and PII. Lacking the budget and time to vet different SPARQL endpoints, we of course turn federation off. In general, anyone using federation must think about the quality of the modeling, data, and implementation of a SPARQL endpoint that may be included, and any implicit contract with their users. However, these concerns can be addressed in other ways than simply importing the data.
I still have an opinion on how SPARQL as a protocol could be strengthened – I am very impressed with the language and RDF modeling, but as a protocol I wish there were stronger error responses and higher level ways to run SPARQL queries, such as simple POJO bindings to queries, and better ways to page through a set of results. These are middleware issues that can be addressed. JDBC, for example, came long after SQL was well established. Hoping this helps, Dan Davis, Systems/Applications Architect (Contractor), Office of Computer and Communications Systems, National Library of Medicine, NIH From: Davis, Daniel (NIH/NLM) [C] Sent: Monday, November 16, 2015 11:04 AM To: 'Hugh Williams' <hwilli...@openlinksw.com>; Eng.Bassam <bassa...@gmail.com> Cc: virtuoso-users@lists.sourceforge.net Subject: RE: [Virtuoso-users] federated SPARQL queries? Bassam, As a professional in this field, I want to suggest that SPARQL Federated Query is not widely used in the field. Think about how this affects inferencing - unless the federating server has some way of knowing which vocabulary to associate with a remote graph, there is no way to do inferencing. Think also about Distributed Systems Theory in general – how should your SPARQL endpoint behave when another SPARQL endpoint is not responding or is slow? From a distributed systems theory perspective, stopping failures such as “not responding” are much, much more tractable than non-conformant/random behavior. There is an analogous problem in distributed Information Retrieval (IR), e.g. text search. It is common for cooperating search servers to communicate Term Frequency (TF) and Document Frequency(DF) on each search server among cluster members so that distributed relevancy may be calculated (usually described as TF-IDF). With true Federated Search/Meta-search, this isn’t possible, and so search relevancy suffers. It has given federated search rather a black eye although there are many scholarly articles about it. In the semantic web, the common solution is to offer both a download of TTL, RDF, or NTriples and have other SPARQL endpoints include your downloads, as Hugh Williams suggests. Although my semantic web site, http://id.nlm.nih.gov/mesh is a beta and likely to remain that way, we offer downloads of NTriples files at ftp://ftp.nlm.nih.gov/online/mesh. Dan Davis, Systems/Applications Architect (Contractor), Office of Computer and Communications Systems, National Library of Medicine, NIH From: Hugh Williams [mailto:hwilli...@openlinksw.com] Sent: Monday, November 16, 2015 8:59 AM To: Eng.Bassam <bassa...@gmail.com<mailto:bassa...@gmail.com>> Cc: virtuoso-users@lists.sourceforge.net<mailto:virtuoso-users@lists.sourceforge.net> Subject: Re: [Virtuoso-users] federated SPARQL queries? Hi Bassam, I assume your ontology is already in RDF format, in which case see the following article on how to import/load and Ontology into Virtuoso: http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VirtTipsAndTricksGuideImportOntology or generally you can use any of the many methods of insert/load/import’ing RDF data into Virtuoso detailed at: http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VirtRDFInsert Best Regards Hugh Williams Professional Services OpenLink Software, Inc. // http://www.openlinksw.com/ Weblog -- http://www.openlinksw.com/blogs/ LinkedIn -- http://www.linkedin.com/company/openlink-software/ Twitter -- http://twitter.com/OpenLink Google+ -- http://plus.google.com/100570109519069333827/ Facebook -- http://www.facebook.com/OpenLinkSoftware Universal Data Access, Integration, and Management Technology Providers On 16 Nov 2015, at 07:48, Eng.Bassam <bassa...@gmail.com<mailto:bassa...@gmail.com>> wrote: Hi I'm Bassam a software engineer, I'm preparing master thesis in semantic web I have my medical data in virtuoso and want to link my data to external ontology for diseases, how can I do that : must upload the ontology in virtuoso server, if yes how do that? my objective is make federated SPARQL queries to traversal on my data also diseases ontology thanks. -- ----------------------------------- > Eng.Bassam Najeeb. >Software Engineer. ------------------------------------------------------------------------------ Presto, an open source distributed SQL query engine for big data, initially developed by Facebook, enables you to easily query your data on Hadoop in a more interactive manner. Teradata is also now providing full enterprise support for Presto. Download a free open source copy now. http://pubads.g.doubleclick.net/gampad/clk?id=250295911&iu=/4140_______________________________________________ Virtuoso-users mailing list Virtuoso-users@lists.sourceforge.net<mailto:Virtuoso-users@lists.sourceforge.net> https://lists.sourceforge.net/lists/listinfo/virtuoso-users
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