"As soon as you include FROM/FROM NAMED you are including a dataset description and so Jena is *required* by the specification to use that dataset description overriding the default dataset that it would normally use regardless of how said default dataset is defined."
ok, fair enough, but that is not what Jena is doing as shown by the example in 304. From: Rob Vesse <[email protected]> To: "[email protected]" <[email protected]> Date: 08/24/2012 12:28 PM Subject: Re: mixing FROM and FROM NAMED with unionDefaultGraph=true Simon Comments inline: On 8/24/12 8:24 AM, "Simon Helsen" <[email protected]> wrote: >Andy, > >Although this is perhaps a matter of taste, I discussed this issue with a >few smart people here who all intuitively assumed that >unionDefaultGraph=true would automatically merge graphUri2 into the >default graph even if explicitly defined as in the following query: > >FROM <graphUri1> >FROM NAMED <graphUri2> > >The unionDefaulGraph parameter should be treated as part of the query >semantics and you are simply overruling it with your implementation. That >there is a way to formulate the same semantics is irrelevant. It adds >complexity when clients use FROM/FROM NAMED and defaultUnionGraph=true > >Btw, the exact behavior of these clauses in the context of >defaultUnionGraph seems to be notably absent in the spec. That is too bad unionDefaultGraph is an implementation specific detail of Jena which is not covered by the spec and IMO shouldn't be covered explicitly by the spec. The spec states a key point which is central to the argument here: Section 8.2 - Specifying RDF Datasets "If a query provides such a dataset description, then it is used in place of any dataset that the query service would use if no dataset description is provided in a query" So as noted above the unionDefaultGraph setting is just an implementation detail of Jena, in the context of the above part of the spec it is defining the dataset that Jena will use if no dataset description is provided in the query. As soon as you include FROM/FROM NAMED you are including a dataset description and so Jena is *required* by the specification to use that dataset description overriding the default dataset that it would normally use regardless of how said default dataset is defined. Rob > >Simon > >PS: my mail clients adds the sender automatically in cc. I agree that it >is annoying and will try to recall removing it, but at the same time, I >have had countless cases were you cc-ed me in exactly the same way. > > > >From: >Andy Seaborne <[email protected]> >To: >[email protected] >Date: >08/24/2012 11:14 AM >Subject: >Re: mixing FROM and FROM NAMED with unionDefaultGraph=true > > > >On 24/08/12 16:06, Simon Helsen wrote: >> I agree with your statements below, but where it becomes >> incomprehensible for end-users is the following: >> >> case 1): >> >> FROM <graphUri1> >> FROM <graphUri2> >> >> everyone agrees that the default graph is the merge of graphUri1 and >> graphUri2 (unionDefaultGraph plays no role since no named graphs are >> defined) >> >> FROM <graphUri1> >> FROM NAMED <graphUri2> >> >> in this case, I woudl expect the default graph to be just graphUri1, >> unless unionDefaultGraph=true, in which case the explicitly named >> graphUri2 has to be merged into it. Don't you agree that any other >> behavior becomes really difficult to follow for end-users? > >No. > >The query asked for default graph to be <graphUri1>. That is what it >gets. > >Why should unionDefaultGraph have any influence on the dataset to query? > >If you want the alternative, ask for it: > >FROM <graphUri1> >FROM <graphUri2> >FROM NAMED <graphUri2> > > Andy > >(you don't need to cc me on emails to dev@) > >> >> Simon > > >
