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querions regarding BINDINGS

From: Carlos Buil Aranda <cbuil@fi.upm.es>
Date: Thu, 09 Sep 2010 12:02:41 -0400
Message-ID: <4C890521.5030009@fi.upm.es>
To: public-rdf-dawg@w3.org
  Hello all,

I'm looking at the BINDINGS description of the SPARQL 1.1 query 
federation and I have a question about it. It says "In order to 
efficiently communicate constraints to sparql endpoints, the queryier 
may follow the WHERE clause with BINDINGS."  I'm want to implement it, 
but I do not totally understand it. Does the sentence mean that it is 
better to use BINDINGS for global constraints?

As I see it, BINDINGS modifies the solution once all the triples have 
been recovered from multiple SERVICE (or a single query), but FILTER can 
do much of it inside the query, Am I right? in the example query, would 
not be possible (in case they were services) to filter directly the 
results of them for making the query more efficient? there would be less 
data to make the joins, right?

(by the way, in the BINDINGS section, the variable ?iuphar is not 
present inside the query but it is in the select and the bindings part, 
is that ok?)

thanks a lot :)

Carlos
Received on Thursday, 9 September 2010 16:03:09 GMT

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