Realized i kept missing the

Free imac — Fri, 29 May 2009 09:52:27 -0500

Realized i kept missing the f in the 'rdf' string....ops. Thanks for this

new to sparql

Music Lyrics Now — Wed, 08 Apr 2009 00:39:46 -0500

I am familiar with stand sql, i am looking at the syntax for SPARQL and it seems more flexible. Looks like you have more powerful expressions for filtering. Nice

Describing (finding) subjects which don't have a particular predicate in SPARQL

elliot — Tue, 07 Apr 2009 04:37:11 -0500

If you want to do something like a SQL NOT in SPARQL, here's what the query looks like:

PREFIX rs: <http://schemas.talis.com/2006/recordstore/schema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

DESCRIBE ?tenancy {
  ?tenancy rdf:type rs:Tenancy .
  OPTIONAL { ?tenancy rs:platformStoreUri ?o } .
  FILTER ( !bound(?o) )
}

Here I'm looking for subjects with rdf type of http://schemas.talis.com/2006/recordstore/schema#Tenancy, which don't have a http://schemas.talis.com/2006/recordstore/schema#platformStoreUri predicate. The important bit is that you make the predicate which could potentially not be "set" OPTIONAL; and add a FILTER which only includes subjects where the predicate is bound to a value. This effectively screens out any subjects where the predicate has not been added to the subject. This pattern is basically Negation as Failure (according to the SPARQL recommendation), which derives from logic programming. Feels a bit like being back at university.

townx - Describing (finding) subjects which don't have a particular predicate in SPARQL - Comments

Realized i kept missing the

new to sparql

Describing (finding) subjects which don't have a particular predicate in SPARQL