W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > July to September 2010

Re: Duplicate columns and group keys

From: Gregory Williams <greg@evilfunhouse.com>
Date: Thu, 30 Sep 2010 14:27:30 -0400
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <02D90E85-5218-4292-A761-C945261A3516@evilfunhouse.com>
To: Andy Seaborne <andy.seaborne@epimorphics.com>
On Sep 30, 2010, at 6:57 AM, Andy Seaborne wrote:

> Following a jena-dev question, I wondered what do implementations do with the following?
> 
> # Duplicate select variable - SPARQL 1.0
> SELECT ?s ?s ?p ?o
> {
>   ?s ?p ?o
> }

At the protocol level RDF::Query duplicates ?s, but at the API level the variable bindings only contain ?s once (being associative arrays). The protocol/interface code just accesses the projection list and loops over the variables, though, so it ends up being produced twice.

.greg
Received on Thursday, 30 September 2010 18:28:27 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:43 GMT