On 02/10/13 13:27, james anderson wrote:
good afternoon.
On 2 Oct 2013, at 12:27 PM, Andy Seaborne wrote:
with respect to part of the originally posed question:
Rationale for the expectation is that FROM clause constructs union of the
default graph and the graphs specified by FROM statements in the query, and
then runs rest of the query against the union of graphs.
However, experimentation results are different: The query returns an EMPTY
result.
Rationale for the obtained results is that query was run against each
individual dataset and then the union of results is returned.
in particular, the expectation that the active graph include the default graph
from the store, if the store were to contain
PREFIX ex: <http://www.example.info>
ex:ds1 { <ex:r><ex:p1><ex:o1> . }
ex:ds2 { <ex:r><ex:p2><ex:o2> . }
<ex:r><ex:p2><ex:o3> .
would the posed query,
PREFIX ex: <http://www.example.info>
FROM <ex:ds1>
FROM <ex:ds2>
SELECT ?p ?o WHERE {
<ex:r> ?p ?o .
}
include "<ex:p2><ex:o3> " ?
No - the default graph becomes the union of the named graph and the
original default graph is not visible.
(well, it is accessible via the synthetic name <urn:x-arq:DefaultGraph>
which specifically accesses the real default graph regardless of
anything else.)
Andy
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james anderson | [email protected] | http://dydra.com
