How does one execute a DESCRIBE query. I see examples of Tuple and Graph queries in the user guide, but I don't see how to prepare/evaluate a DESCRIBE query.
Mark Larkin From: Atanas Kiryakov [mailto:[email protected]] Sent: Friday, December 25, 2009 7:10 AM To: [email protected]; Mark Larkin Subject: Re: [Owlim-discussion] Walking the Ontology Dear Mark first: Merry Christmas to all OWLIM fans! I am afraid that there is no support for such functionality. Generally, one can do SPARQL DESCRIBE queries, which return connected graphs, which include the URIs bound in the process of query evaluation plus their "surrounding" - sort of molecules, which are likely to differ from one engine to another, because the specifications leaves it quite undetermined. SPARQL DESCRIBE is more limited than the functionality that you are sking for as long as: - you get the "surrounding" sub-graphs with respect to *any* properties - it is not recursive, i.e. you are getting the immediate neighbouhood, where the individual(s) of intrest appear as subjects. It is not clear from your email, but I assume you expect some sort of "recursive closure". Please, confirm After all, I would recommend you to implement the algorithm on your own, accessing the repository through the Sesame APIs. Working directly with the SAIL methods (e.g. getStatements...) should be really fast if you are working with embedded Sesame/OWLIM (the standard option). This way you get maximum flexibility and good speed. You will be able to decide on your own: - wether you want to traverse over inferred statements - do you handle blank nodes in some special way? - do you have time and volume constraints and what should happen when you reach them On the negative side, you will have to take care to avoid loops and few other things of the same sort, but for relatively small result sets, this is doable with a simple hash-set Regards Naso ---------------------------------------------------------- Atanas Kiryakov Executive Director of Ontotext AD, http://www.ontotext.com Sirma Group, http://www.sirma.bg Phone: (+359 2) 974 61 44; Fax: 975 3226 ---------------------------------------------------------- Fortes fortuna adiuvat. ----- Original Message ----- From: Mark Larkin <mailto:[email protected]> To: [email protected] Sent: Wednesday, December 23, 2009 5:09 PM Subject: [Owlim-discussion] Walking the Ontology Are there methods that allow one to walk a populated Ontology? Utilmately I would like to extract a submodel associated with a particular node or individual. For example, given a populated Ontology (Schema+Data), I would like to find all nodes that connect to a particular individual via a series of properties. I know I can write algorithms for this, but I can't help to think that there may already be methods in the Seame API that do this. I understand there are Tuple and Graph Queries, but these don't actually return a connected subgraph. Mark Larkin ________________________________ _______________________________________________ OWLIM-discussion mailing list [email protected] http://ontotext.com/mailman/listinfo/owlim-discussion
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