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Re: Example updates

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Thu, 03 Dec 2009 19:06:34 +0000
Message-ID: <4B180C3A.80502@talis.com>
To: Paul Gearon <gearon@ieee.org>
CC: Steve Harris <steve.harris@garlik.com>, SPARQL Working Group <public-rdf-dawg@w3.org>


Paul Gearon wrote:

On 03/12/2009 16:38, Paul Gearon wrote to Steve:

 >>> >>  I expected them to come out of the WHERE, so yes, they do. The only
 >>> >>  binding that occurs in the above example is in the WHERE 
clause. The
 >>> >>  INSERTs are just using an already bound set of variables.
 >> >
 >> >  To me that seems very strange.
 > I see where you are coming from, but recall that the ; characters are
 > just there to separate the various INSERTs and DELETEs. They are all
 > supposed to be part of the same command, and that command has a single
 > WHERE clause.



I don't recall that :-) My understanding is that ";" separates 
operations, not directives.  It was introduced because of the problems 
because WHERE is optional.

Andy Seaborne wrote:
 >> What's the limit of what can be done in a single operation?
 > My understanding was that there should not be a limit.

I can understand all in /request/ as a desirable goal but not all in one 
/operation/.



---- One request, two operations

# Move someone from one organisation to another
# 1/ Update the people database
# 2/ Move the details from the graph from one division to another

WITH <people>
DELETE { ?x :organisation ?org }
INSERT { ?x :organisation <http://example/org/computerMaufacturing> }
WHERE
{  ?x foaf:name "John Smith" ;
       :organisation ?org
}

WITH <computerDivision>
DELETE { ?x ?p ?o }
INSERT { GRAPH <servicesDivision> { ?x ?p ?o } }
WHERE { ?x foaf:name "John Smith" ; ?x ?p ?o }

----

Here, each is well delimited.  But if the first were

# No WITH, no WHERE.  Abbreviated DELETE - implicit WHERE
DELETE { GRAPH <people> { ?x :organisation ?org } }

and the second was written:

DELETE { GRAPH <computerDivision> { ?x ?p ?o }
INSERT { GRAPH <servicesDivision> { ?x ?p ?o } }
WHERE
   { GRAPH <computerDivision>
     { ?x foaf:name "John Smith" ; ?x ?p ?o }
   }

then it is ambiguous as to what the WHERE applies to.

See also:

 >>>> (2)
 >>>> WITH <people_graph>
 >>>> INSERT INTO <email_graph> {?person foaf:mbox ?email };
 >>>> INSERT INTO <name_graph> {?person foaf:name ?name }
 >>>> WHERE {
 >>>>  ?person a foaf:Person
 >>>>  OPTIONAL { ?person foaf:mbox ?email }
 >>>>  OPTIONAL { ?person foaf:name ?name }
 >>>> }


Why isn't that:

WITH <people_graph>
INSERT INTO <email_graph> {?person foaf:mbox ?email } ;

-- end operation --

INSERT INTO <name_graph> {?person foaf:name ?name }
WHERE { ... }

	Andy
Received on Thursday, 3 December 2009 19:07:19 GMT

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