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Re: Federated Query

From: Carlos Buil Aranda <cbuil@fi.upm.es>
Date: Wed, 18 May 2011 10:56:50 -0400
Message-ID: <BANLkTi=nvoxU1rZph4LXO8ORg1AB4w9taA@mail.gmail.com>
To: Olivier Corby <Olivier.Corby@sophia.inria.fr>
Cc: public-rdf-dawg@w3.org
dear all,

I fixed all Olivier's comments. They were mainly syntactic and I agreed with
them.

cheers,

Carlos

2011/5/18 Olivier Corby <Olivier.Corby@sophia.inria.fr>

>  Action 463:  remarks about SPARQL 1.1 Federated Query document for LC.
> http://www.w3.org/2009/sparql/docs/fed/service.xml
>
>
> Best regards,
>
> Olivier
>
>
>
> 1.1.1 Namespaces
>
> from the SPARQL1.1 Query
> ->
> from the SPARQL 1.1 Query
>
> -- add a " "
>
>
>
>
> 1.1.3 Terminology
>
> The following terms are defined in SPARQL Query Language 1.1
> ->
> SPARQL 1.1 Query Language
>
>
>
>
> Solution Mapping  (corresponds to the Concepts and Abstract Syntax term
> "RDF URI reference")
> ->
> IRI (corresponds to the Concepts and Abstract Syntax term "RDF URI
> reference")
>
>
>
> 2.1 Simple query to a remote SPARQL endpoint
>
> the people I know
> ->
> the people we know
>
>
>
> and I want to combine
> ->
> and we want to combine
>
>
>
>
> 2.2 SPARQL query with OPTIONAL to two remote SPARQL endpoints
>
> Data in default graph at service: <http://people.example/sparql><http://people.example/sparql>
> ->
> <http://people.example.org/sparql> <http://people.example.org/sparql>
>
>
>
> Query:
>   SERVICE <http://people.example/sparql> <http://people.example/sparql> {
>   ->
>   SERVICE <http://people.example.org/sparql><http://people.example.org/sparql>{
>
>
>
> 2.3 Variable Services
>
> http://projects1.example/SPARQL
> ->
> http://projects1.example.org/SPARQL
>
> same for projects2 and projects2
>
>
>
> 2.3 Variable Services
>
> This query, on the data above, has four solutions:
> ->
> three solutions
>
>
>
> 2.4 Boundedness Condition
>
> For example, the SPARQL graph pattern
> ->
> For example, in the SPARQL graph pattern
>
>
>
>
> ?Y is not strongly bound
> ->
> add a reference to the definition of   strongly bound below
>
>
>
>
>  { ?X :p :o SERVICE ?Y { ?Z :p :o } SERVICE ?X { ?Y :p :o } } The
>  ->
>  a "." is missing before The
>
>
>
>
> 2.5 Service Execution Failure
>
> unbounded
> ->
> unbound
>
>
>
>
> If the 'SILENT' token it is not present
> ->
> If the 'SILENT' token is not present
>
>
>
> Data in <http://people.example/sparql> <http://people.example/sparql>endpoint:
> ->
> http://people.example.org/sparql
>
>
>
> 2.6 BINDINGS
>
> SPARQL 1.1 Query includes the BINDINGS clause (Section 18.2.5.6 BINDINGS)
> ->
> Section 10.2 BINDINGS
>
>
>
>
> 3.1 Definition of SERVICE
>
> Tranform(syntax form):
> ->
> Tranform (syntax form):
>
>
>
>
>  Section 18.2.2.4 Translate Graph
>  ->
>  Section 18.2.2.5
>
>  (may be not a good idea to duplicate section numbers as they may change)
>
>
>
>
> Let SilentOp := boolean, SERVICE indicating error behavior.
> ->
> Let SilentOp := boolean, indicating SERVICE error behavior.
>
>
>
>
> Example: a SERVICE graph pattern in a series of joins:
>
> ... WHERE { { ?s :p1 ?v1 } SERVICE <srvc> {?s :p2 ?v2 } { ?s :p3 ?v2 } }
>
>
> Join( Service( <srvc>,
> BGP( ?s :p1 ?v1 ),
> BGP( ?s :p2 ?v2 ), false ),
> BGP( ?s :p3 ?v2 ) )
>
> ->
> BGP( ?s :p1 ?v1 ) should not be inside service
>
>
>
> Example: a SERVICE SILENT graph pattern in a series of joins:
>
> same remark as above
>
>
>
>
> Definition: Evaluation of a Service Pattern
>
> vars is the set of variables in pattern P
> ->
> I think that vars should be the variables in-scope in P because they are
> used as "select vars where P"
>
>
>
> if IRI is a SPARQL service
>   Service(IRI,G,P,SilentOp)) = Invocation( IRI, vars, P, Bindings(G, vars),
> SilentOp )
>  ->
>   eval(D(G), Service(IRI,G,P,SilentOp)) = Invocation( IRI, vars, P,
> Bindings(G, vars), SilentOp )
>
>
>
> The evaluation of graph uses the SPARQL algebra union operator.
> ->
> The evaluation of service
>
>
>
> Definition: Strongly bound variable
>
> P = P1 GROUP BY E1 ... n
> ->
> P = P1 GROUP BY E1 ... En
>
>
>
>
> (what I want say here is that it is not possible  to guarantee that a
> variable will be bounded after a SERVICE execution).
> ->
> (It is not possible to guarantee that a variable will be bounded after a
> SERVICE execution).
>
>
>
> UNBOUND is not a possible value for a ?Xi in BindingValues.
> ->
> UNBOUND is not a possible value for ?Xi in BindingValues.
>
>
>
>  P = GRAPH ?X { P1 } and ?X is strongly bound
> ->
>  P = GRAPH ?X { P1 }
>
>
>
> Definition: Service safeness
>
> it hold that
> ->
> it holds that
>
>
>
> 4.1 Grammar
>
>
> The formal definition for the SPARQL 1.1 Federated Query grammar is
> provided with the SPARQL 1.1 Query grammar
> ->
> add a "." at the end
>
>
>
> It is a syntax error if to use
> ->
> It is considered as a syntax error to use
>
>
>
> as the first argument to a
> ->
> as the first argument of a
>
>
>
>
> 5 Conformance
>
>
>  See section 7 Internet Media Type for conformance to the
> application/sparql-query media type.
> ->
> there is no such section 7, should be removed
>
>
>
>  SPARQL 1.1 Query Language for RDF
>  ->
>  SPARQL 1.1 Query Language
>
>
>
> 6 Security Considerations (Informative)
>
> SPARQL Query 1.1 [SQRY] Section 18
> ->
> SPARQL 1.1 Query [SQRY] Section 21
>
>
>
Received on Wednesday, 18 May 2011 14:57:37 GMT

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