townx

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.