Hi Hugh I can confirm that the same issue still happens in my code as well (thought it was fixed ages ago :-( ). The sample application is no use as a reference since it only messes about with SqlExtendedStrings for IRIs and does nothing with non-IRI types other than call ToString() on them (either explicitly or implicitly when displaying them).
The problem seems to be that things are being returned as Strings rather than as appropriate .Net types. The only RDF datatypes I can get back properly are those with custom datatypes - standard types like Integers, Booleans, Date Times etc all come back as plain strings instead of as SqlRdfBox or an appropriate .Net type. Literals with language tags do get returned correctly though. I remember bringing up this issue back in April 2010 and I had thought it was fixed but it appears not. This issue is a major pain for people using Virtuoso's ADO.Net support whether directly or indirectly via a library like mine so please can your developers look into this again asap. Cheers, Rob P.S. If you finally fix the booleans to integers thing I will be eternally grateful especially if you fix the above as well ---------------------------------------- From: "Hugh Williams" <[email protected]> Sent: 26 January 2011 13:45 To: "Moritz Eberl" <[email protected]> Subject: Re: [Virtuoso-users] Missing datatypes using ADO.NET Hi Moritz, As a starting point are you able to get the sample walkthrough SPASQL application we have at: http://virtuoso.openlinksw.com/dataspace/dav/wiki/Main/VirtSPASQLWinFormApp working ? The booleans being mapped to integers is a known issue that is scheduled to be fixed in a future/next release ... Best RegardsHugh WilliamsProfessional ServicesOpenLink SoftwareWeb: http://www.openlinksw.comSupport: http://support.openlinksw.comForums: http://boards.openlinksw.com/supportTwitter: http://twitter.com/OpenLink On 26 Jan 2011, at 13:12, Moritz Eberl wrote: Hello Rob, currently i do not use any API. I first wanted to be able to get the RDF data with basic SPARQL queries. While trying to figure out what i was doing wrong, i also used your API. The results where pretty much the same. All typed literals were returned as strings. You are right about the boolean datatype in Virtuoso. I just tried to store a xsd:boolean, which resulted in a xsd:integer using the RDF/XML representation. Cheers, Moritz Am 26.01.2011 13:03, schrieb Rob Vesse: Hi Moritz What API are you using to manipulate the RDF within your application or have you rolled your own? My API dotNetRDF (http://www.dotnetrdf.org) has Virtuoso integration built in and might be helpful to you as it handles all the data type retrieval appropriately. I've had isolated reports that on some machines things don't come back correctly and I know that it was an issue with older 6.x releases of Virtuoso (though should be fine in the version you're using). One think to note about datatypes is that in my experience Virtuoso doesn't return all datatypes correctly even when you do a SPASQL select like you've done and do all the type handling. If my memory serves me this particularly applies to xsd:boolean typed literals which come back as a 1/0 rather than a true/false though if you do a CONSTRUCT over the same data the type does come back correctly. Regards, Rob Vesse ---------------------------------------- From: "Moritz Eberl" <[email protected]> Sent: 26 January 2011 11:51 To: [email protected] Subject: [Virtuoso-users] Missing datatypes using ADO.NET Hello, i am trying to use Virtuoso as RDF store for a C# application with .Net 4, but i have some issues with the ADO.NET library. I have no troubles creating triples with SPARQL using SPASQL, but the retrieval is problematic. In the result set, all typed literals are strings without type information. I get the IRI as SqlExtendedString and the literals with language information as SqlRdfBox, so no problem there. Now i am wondering what i'm doing wrong. This is how i access the data: DataTable results = new DataTable(); results.Columns.Add("s", typeof(System.Object)); results.Columns.Add("p",typeof(System.Object)); results.Columns.Add("o", typeof(System.Object)); VirtuosoCommand cmd = Connection.CreateCommand(); cmd.CommandText = "SPARQL select * where {?s ?p ?o.}"; //just an example here VirtuosoDataAdapter adapter = new VirtuosoDataAdapter(cmd); adapter.Fill(results); I also tried to use the RDF/XML output, although not optimal performance-wise, it kind of worked. One thing i noticed though, was that ASK statments produce malformed XML. As example, this statment SPARQL define output:format "RDF/XML" ask where {?s ?p ?o.}; produced xmlns:rs="http://www.w3.org/2005/sparql-results#"; xmlns:xsd="http://www.w3.org/2001/XMLSchema#"; > rdf:datatype="http://www.w3.org/2001/XMLSchema#boolean";>1 The prefix of the closing result tag is missing. You can try it in the Interactive SQL form of the conductor. My system specs: OS: Windows 7 64-bit Virtuoso: Open-Source-Edition Version 06.01.3127 - Build Jul 9 2010 32-bit virtado3.dll: Version 6.2.3128.1 It would be great if somebody could help me to resolve my issues. Cheers, Moritz ---------------------------------------------------------------------------- -- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Virtuoso-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/virtuoso-users ---------------------------------------------------------------------------- -- Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d__________________________________________ _____ Virtuoso-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/virtuoso-users
