Hi Andy, Reading directly into the dataset worked like a charm, thanks a lot !!
Best Regards, Nandana On Thu, Jan 22, 2015 at 5:57 PM, Andy Seaborne <[email protected]> wrote: > On 22/01/15 16:17, Nandana Mihindukulasooriya wrote: > >> Hi, >> >> I am using Jena TDB (1.1.1) to store a set of named graphs. Everything >> works fine but whenever I retrieve a named graph from the dataset, all the >> namespace prefix information is lost. Is there a way to preserve the >> namespace prefixes in the original RDF graph when I add them to dataset. >> >> I've attached a minimal code snippet here that illustrate the issue in the >> following link. >> http://stackoverflow.com/questions/28091817/how-to- >> preserve-namespace-prefixes-in-a-jena-tdb-dataset >> >> >> Best Regards, >> Nandana >> >> > Hi Nandana, > > Thanks for the example - I'll try and get it running when I can (wrong > size of computer just at the moment) but a partial answer now ... > > I can't remember exactly but I think that addNamedModel is a quad copy > (does not copy prefixes). If so, it is probably an oversight nowadays. > > What happens if you read directly into the dataset? > > dataset.begin(ReadWrite.WRITE) ; > try { > StringReader sw = new StringReader(modelText) ; > Model m = dataset.getNamedModel("http://example.org/ro";) ; > RDFDataMgr.read(m, sw, null, Lang.TTL) ; > dataset.commit() ; > } finally { > dataset.end() ; > } > //Unchecked > > Hmm - quick grep - looks like DatasetGraphCaching.addGraph could do the > prefix thing. > > Sorry for the rushed answer, > Andy > > >
