Seaborne, Andy wrote: > >> -----Original Message----- >> From: Peter Ansell [mailto:[EMAIL PROTECTED] >> Sent: 02 November 2008 20:32 >> To: Seaborne, Andy >> Cc: [email protected] >> Subject: Re: [Dbpedia-discussion] bif:contains text search treated as a >> prefix >> >> >> ----- "Andy Seaborne" <[EMAIL PROTECTED]> wrote: >> >> >>> From: "Andy Seaborne" <[EMAIL PROTECTED]> >>> To: [email protected] >>> Sent: Monday, 3 November, 2008 5:03:17 AM GMT +10:00 Brisbane >>> Subject: Re: [Dbpedia-discussion] bif:contains text search treated as >>> >> a prefix >> > > > >>> You have used bif: here. It needs a matching PREFIX . There are no >>> default prefixes in SPARQL. >>> >> As far as I know, OpenLink have not provided a prefix definition for >> bif: (ie, Built-in Functions from SQL). >> > > Peter - thanks for the information. > > OpenLink - any chance of providing a non-proprietary approach within the > SPARQL syntax? > Yes, it should be resolved with an OpenLink domain based qname for this magic predicate i.e., <http://www.openlinksw.com/schema/sparql/extensions#contains> should do, such that you simply take the following approach:
prefix bif: <http://www.openlinksw.com/schema/sparql/extensions#> Kingsley > It's not very semantic web in three ways. Not using a URI for something on > the web (that function or index); having non-portable syntax (bif: being > special and not needing a prefix), and not reusing existing names > (fn:contains from XPath/XQuery functions and operators seens to do what this > does). > > The function/index should have a URI. That's part of the point, giving > global names to things. It's written as a property in a triple pattern so > really it should be a URI, after all, that's the point. As a triple > (pattern) is a relationship between subject and object, the fact it's > calculated rather than looked up in some graph is irrelevant but the meaning > of the relationship is something to fix with a web-wide name. > > The "bif:" special means that an application must reworked to apply the same > query to a different source, as might happen walking linked data. > > XPath/XQuery has fn:contains which is a function so > > FILTER(fn:contains(?x, "xyz")) > > See : http://www.w3.org/TR/xpath-functions/#func-contains > > (Or, maybe, the triple pattern equivalent.) > > Now at the moment there is no standard for what a processor provides, but at > least reusing the F&O function would be good. Hopefully, the next round of > round of SPARQL specification will include a standard set of functions that > all implementation provide so helping portability of applications across end > points. If a client application is going to work over multiple endpoints, > it's easier if they offer the same core functionality. At least enable an > endpoint to make an RDF description available which says what it offers. > > (aside: > The query processor can easily spot a FILTER like that and use an index so > the triple pattern/function difference is merely whether the application > writer has to do the work.) > > Marvin - > > The direct call to QueryEnegineHTTP in ARQ will bypass the client-side syntax > checking to allow the non-portable query to be sent. > > Andy > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > _______________________________________________ > Dbpedia-discussion mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion > > -- Regards, Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen President & CEO OpenLink Software Web: http://www.openlinksw.com ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Dbpedia-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dbpedia-discussion
