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Re: update= vs query=

From: Steve Harris <steve.harris@garlik.com>
Date: Sun, 27 Sep 2009 20:35:06 +0100
Message-Id: <C334EC25-7BBF-4B46-B7E8-D1A25998A6A3@garlik.com>
To: "public-rdf-dawg@w3.org Group" <public-rdf-dawg@w3.org>
On 27 Sep 2009, at 17:35, Seaborne, Andy wrote:
[snip]
>>
>> I have a concern with what happens when you receive a POST request
>> using "either", e.g.
>>
>> SELECT { ?x ?y ?z }
>> INTO <http://foo.example/somegraph>
>> WHERE { GRAPH <http://bar.example/somegraph> { ?x ?y ?z } }
>>
>> If would be very hard for the endpoint to make a sensible guess as to
>> whether it should try an interpret this as SPARQL/Query or SPARQL/
>> Update, and would have trouble returning a sensible error message in
>> either case.
>
> Steve - I don't understand the example.  SELECT is always a query -  
> INSERT would be the operation in SPARQL/Update. The verbs of query  
> and update are distinct so the example does not parse either way.

That was the point, I was thinking of a scenario where a user types an  
update expression but uses SELECT instead of INSERT by mistake (maybe  
CONSTRUCT would have been a more obvious example). The syntax error  
message returned will be at best unhelpful and probably confusing.

>> Additionally, I like the separation that query= and update= gives,
>> potentially avoiding some of the problems that SQL has from (often)
>> sharing a common API for pure query operations and update operations,
>> if the SPARQL client has to be explicit.
>
> I agree - the "either=" suggestion is for completeness.  I think we  
> need a sufficiently motivating reason for looking at it and, so far,  
> I don't see one.
>
>> If there's some application where the client really want to have a
>> single method then it can do the regex client side to make the guess.
>
> Agreed.  The verbs in query and update are distinct.


- Steve

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Steve Harris
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Received on Sunday, 27 September 2009 19:35:43 GMT

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