Gregory Todd Williams kasei

Data Flows and Types in Managing RDF and SPARQL data

Data types

The types of data we will concern ourselves with:

[T]riples
[Q]uads

A line-based protocol for querying and updating triple/quad stores

Below are some thoughts on extending the RDF Patch format syntax to a line-based protocol that allows updating and querying RDF triple and quad stores. This allows triple or quad stores to be used directly by systems that require direct access to the data (e.g. with access to real blank node labels unavailable via SPARQL Query/Update). It also allows modular implementation without requiring systems to use the same language as the store (e.g. using the Jena API) or use wrappers/adapters (e.g. using things like SWIG or XS).

Data

@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix : <http://example.org/> .

:s1 :str "abc" .
:s2 :str "abc"@en .
:s3 :str "abc"^^xsd:string .

Proposed SPARQL 1.1 Protocol Tests

This repository contains code which attempts to validate implementations of the SPARQL 1.1 Protocol. It is a work in progress, and subject to change as the Protocol spec continues towards becoming a W3C recommendation, and as we (the SPARQL Working Group) continue to evaluate existing existing implementations.

	SELECT * WHERE {
	GRAPH ?G {
	?p a rdf:Property .
	?p <http://schema.org/rangeIncludes> <http://schema.org/URL> .
	OPTIONAL {
	?p <http://schema.org/rangeIncludes> ?x .
	FILTER (?x != <http://schema.org/URL>) .
	}
	FILTER (!BOUND(?x)) .
	}

	:agg-empty-group rdf:type mf:QueryEvaluationTest ;
	mf:name "agg empty group" ;
	mf:name "Aggregate over empty group resulting in a row with unbound variables" ;
	mf:feature sparql:aggregate ;
	rdfs:seeAlso <http://answers.semanticweb.com/questions/17410/semantics-of-sparql-aggregates> ;
	# dawgt:approval dawgt:Approved ;
	# dawgt:approvedBy <http://www.w3.org/2009/sparql/meeting/2012-08-07#resolution_2> ;
	rdfs:comment "Unapproved on 2012-10-30 due to typo in agg-empty-group.srx";
	mf:action
	[ qt:query <agg-empty-group.rq> ;

	$query->rewrite_algebra( postfix => sub {
	my $visitor = shift;
	my $algebra = shift;

	if ($algebra->isa('RDF::Query::Algebra::BasicGraphPattern'))
	return $visitor->stop; # stop traversal

	if ($algebra->isa('RDF::Query::Algebra::Filter')) {
	my $expr = $algebra->expr;
	if ($expr->isa('RDF::Query::Expression::Function')) {

	2012-06-25 15:08:04.035 pack[46953:f0b] Listening on localhost:8081
	Perl 0x100823200

	Program received signal EXC_BAD_ACCESS, Could not access memory.
	Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000
	[Switching to process 46953 thread 0x2807]
	0x00000001003b80ca in XS_Scalar__Util_blessed ()
	(gdb) bt
	#0 0x00000001003b80ca in XS_Scalar__Util_blessed ()
	#1 0x00000001000bea9c in Perl_pp_entersub ()

	% telnet sparql.org 80
	Trying 140.211.11.85...
	Connected to sparql.org.
	Escape character is '^]'.
	POST /sparql HTTP/1.1
	TE: deflate,gzip;q=0.3
	Connection: TE, close
	Host: sparql.org
	User-Agent: SPARQL11ProtocolValidator/0.1 libwww-perl/5.834
	Content-Length: 96

	Index: aggregates/agg-err-02.srx
	===================================================================
	RCS file: /w3ccvs/WWW/2009/sparql/docs/tests/data-sparql11/aggregates/agg-err-02.srx,v
	retrieving revision 1.4
	diff -r1.4 agg-err-02.srx
	13c13
	< <literal datatype="http://www.w3.org/2001/XMLSchema#double">2.5e0</literal>
	---
	> <literal datatype="http://www.w3.org/2001/XMLSchema#double">2.5E0</literal>
	29c29