Re: CONSTRUCT an RDF Datest

good evening;

> On 2015-12-05, at 21:30, Tara Athan <taraathan@gmail.com> wrote:
> 
> […]
> 
> 
> On 12/5/15 12:38 PM, james anderson wrote:
>> good evening;
>> 
>>> On 2015-12-05, at 14:29, Tara Athan <taraathan@gmail.com> <mailto:taraathan@gmail.com> wrote:
>>> 
>>> Given that this extension provides closure in SPARQL over RDF datasets, is it now possible to form nested CONSTRUCTs over RDF datasets, or in some other way specify a chain of RDF dataset queries?
>>> 
>>> I looked at the extended CONSTRUCT form, but I didn't see any spot to plug in another CONSTRUCT to indicate the derived RDF dataset to be queried.
>> the bnf phrases which define sub-selects,
> Subselects seem to be a difference concept to me.
> I haven't yet seen a connection of Subselect to the concept of CONSTRUCT as a (parameterized) operator from RDF datasets to RDF datasets, which can then be composed because the domain and range are the same.

if you consider federation the connection may appear.

> 
> Tara
>> 
>> 
>> [53]  GroupGraphPattern ::=   '{' ( SubSelect | GroupGraphPatternSub ) ‘}’ (1)
>> [8]   SubSelect     ::=   SelectClause WhereClause SolutionModifier ValuesClause (2)
>> 
>> restrict the sub-expression to be a select form only.
>> the simple explanation is that the other forms do not include the requisite dimensions for the projected fields and, as such, cannot produce legitimate arguments for the algebra operators.
>> 
>> this could be rectified, by permitting at least construct and describe variants which included projection dimensions, but that would be an extension.
>> 
>> 
>> ---
>> (1) http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#rGroupGraphPattern <http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#rGroupGraphPattern>
>> (2) http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#rSubSelect <http://www.w3.org/TR/2013/REC-sparql11-query-20130321/#rSubSelect>
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james anderson | james@dydra.com | http://dydra.com