Re: [dotNetRDF-bugs] Problem serializing to NQuads

[Rob V. <rv...@do...>]

Which version is this?  I'm assuming pre 1.0.4 or lower?

Since you are talking about Store Manager then this sounds like TOOLS-409
which was already reported and fixed for the 1.0.5 release.  It was a bug
in how Store Manager passed the data to the underlying writers.

Note that serializing an in-memory store directly in code was not affected
in any way.

The creation of the empty default graph is an implementation detail, any
SPARQL Update which inserts data potentially causes the default graph to
be created because the SPARQL specification states that a dataset always
contains an unnamed default graph and some parts of the implementation
assume graphs will already exist so it is safer and faster to pre-create
any graphs that will potentially be affected.

LOAD is a special case because it is really just a shim to the parser
sub-system and the way the parser sub-system generates data means that
only specifically mentioned graphs are ever created.

Rob

On 16/06/2014 15:14, "Tomasz Pluskiewicz" <tom...@gm...>
wrote:

>Hi
>
>We've noticed weird behaviour with in-memory triple store, when
>serializing to NQuads. Here's what happens:
>
>1. Create an empty TripleStore
>2. Run UPDATE
>
>INSERT DATA {
>GRAPH <http://test.org/user> {
><http://test.org/user>
><http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
><http://schema.org/Person> .
><http://test.org/user> <http://some/ontology/favorite>
><http://test.org/product/name> .
>}
>GRAPH <http://test.org/prodList/> {
><http://test.org/user> <http://xmlns.com/foaf/0.1/primaryTopic>
><http://test.org/user> .
>}
>}
>
>3. Serialize to NQuads. Store Manager correctly informs that 3 triple
>were serialized in 3 graphs (including empty default graph).
>
>The output file contains all triples, but without graph names. Thus
>they are all serialized in the default graph. It's not a problem with
>the store in-memory. The insert creates correct graph with data.
>I've confirmed this occurs in all version since 1.0.0.
>
>Curiously only when data is loaded with a LOAD <x> INTO GRAPH <y>
>command or with dNetRDF API, the store is serialized correctly. Only
>INSERT DATA causes the problem.
>
>Is this a known problem?
>
>And by the way. Why INSERT DATA creates an empty default graph in the
>store while loading or LOAD <x> only creates those graphs actually
>included in the source files?
>
>Greets,
>Tom
>
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