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test change proposal: same graph in default and named graph parts of RDF dataset

From: Lee Feigenbaum <lee@thefigtrees.net>
Date: Thu, 04 Oct 2007 13:30:46 -0400
Message-ID: <47052346.9010605@thefigtrees.net>
To: 'RDF Data Access Working Group' <public-rdf-dawg@w3.org>

Hi all,

I've been seeing where I fall short on the graph/ and dataset/ tests,
and it's all for the same reason. These tests:


All put the same URI as the default graph and as a graph in the named
graph part of the dataset, and all then correlate triple patterns by a
common subject. The results of each as approved rely on the fact that
blank nodes are disjoint between the default graph and a named graph.

That is, a graph <g.ttl> containing:

_:b1 :p :o .

will produce no results in this query:

SELECT * FROM <g.ttl> FROM NAMED <g.ttl> {
   ?s :p :o .
   GRAPH <g.ttl> { ?s :p :o }

To test Glitter+Anzo, I read all the data graphs into our quad store.
When the graph is queried in this type of query, the blank node is the
same whether it's treated as the default graph or a named graph, and so
I get results for these queries (and thus fail the tests).

I've talked this over with Andy and Eric, and we all agree that nothing 
in the spec mandates that the default graph need be different from all 
the named graphs that make up the RDF Dataset.

That is, if the RDF Dataset is {G, <u1, G1>, <u2, G2>, ... <un, Gn>}, 
then nothing dictates that G must be != from all the Gi.

In order to still maintain our test coverage (testing that bnode ids are 
not shared between different dataset graphs), I'm going to propose on 
Tuesday that we remove the above tests and replace them with


These are identical tests except that the graphs in the default graph 
and the named graph part of the dataset have different URIs.

Anzo+Glitter passes them.

We'll look at this on Tuesday, but please speak up before then if you 
think there is a problem here...

Received on Thursday, 4 October 2007 17:38:03 UTC

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