- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Tue, 12 Sep 2006 15:09:04 +0100
- To: Kendall Clark <kendall@monkeyfist.com>
- CC: dawg mailing list <public-rdf-dawg@w3.org>
Hopefully a report will speed the telecon up (sorry - it's a bit rushed) ARQ implementation reports and current HP position statements: (Positions subject to change) > 3. nonLiteral Value Testing > > http://lists.w3.org/Archives/Public/public-rdf-dawg/2006JulSep/0199.html > http://www.w3.org/2001/sw/DataAccess/issues#nonliteralValueTesting >>>> ILLFORMED LITERAL TESTING ARQ implements: datatype("-5"^^xsd:positiveInteger) = xsd:positiveInteger xsd:positiveInteger("-5") => error datatype is an accessor (like str() and lang()) datatype("<"^^rdf:xmlLiteral) => rdf:xmlLiteral [[ Discussion: Arguably that's wrong, but rdf:xmlLiteral is not required datatype in SPARQL. As rdf:xmlLiteral must be exclusively canonicalized (http://www.w3.org/TR/rdf-concepts/#section-XMLLiteral) they require an XML parser. ]] ARQ treats "-5"^^xsd:positiveInteger is an RDF literal (informally, think of RDF literal as the super type of all literals). Position: No change to the design of datatype. >>>> NON LITERAL VALUE testing Postion: >>>> 1) Restrict value testing to data values with literal form is fine if the reading for "value testing" applies to value comparison operations "<" and ">". "=" works as sameTerm on non-literal forms. "abc"^^xsd:integer = "abc"^^xsd:integer ==> true FILTERs and non-value functions still apply to non-literals (like IRIs) and literals which are invalid by datatype entailment. http://lists.w3.org/Archives/Public/public-rdf-dawg/2006JulSep/0139.html """ I suspect most people expect that if I put ^^xsd:integer in there that i get an object that is an integer! """ In ARQ, "abc"^^xsd:integer is an RDF literal which does not have an integer value. > 4. contradictoryKB > > http://www.w3.org/2001/sw/DataAccess/issues#contradictoryKB > http://lists.w3.org/Archives/Public/public-rdf-dawg/2006JulSep/0119.html Proposal: Entailment regimes define what is (in)consistent. SPARQL does not define what happens to query on an inconsistent graph Rational: It would ideal to define what happens but the case of wanting to find illegal literals in a graph compared with allowing extensibility to reasoner-backed datasets means that one design will not cover all cases. > > 5. formsOfDistinct > > http://lists.w3.org/Archives/Public/public-rdf-dawg/2006JulSep/0200.html > http://www.w3.org/2001/sw/DataAccess/issues#formsOfDistinct HP position: Two different solutions in a DISTINCT result set differ by one or more bindings. One binding is different from another if they refer to different variables or the values are RDFterm-different. DISTINCT is term-DISTINCT as defined for SPARQL (simple entailment). > > 6. unbound variables in FILTER > > http://lists.w3.org/Archives/Public/public-rdf-dawg/2006JulSep/0206.html Acceptable. [[ My preference is that functions can see unbound variables - each function then decides what to do. ARQ provides, for debugging: FILTER(:print(?x)) prints the value of ?x or "unbound" and returns true. ]]
Received on Tuesday, 12 September 2006 14:09:35 UTC