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Re: rdf dataset parameters in protocol for sparql update

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Mon, 29 Aug 2011 18:22:59 +0100
Message-ID: <4E5BCAF3.6090005@epimorphics.com>
To: public-rdf-dawg@w3.org


On 29/08/11 18:19, Lee Feigenbaum wrote:
> On 8/29/2011 12:58 PM, Andy Seaborne wrote:
>>
>>
>> On 16/08/11 03:11, Lee Feigenbaum wrote:
>>> 1/ The parameters are called using-graph-uri and using-named-graph-uri
>>>
>>> 2/ If at least one value for one of the parameters is present, then the
>>> protocol parameters fully define the RDF dataset that is used for the
>>> query pattern matching (WHERE clause) of all operations in the update
>>> request. That is, they fully replace all USING and USING NAMED clauses
>>> in the request's operations.
>>>
>>> A third way of stating this: the semantics of including at least one of
>>> using-graph-uri and using-named-graph-uri is the equivalent of doing the
>>> following:
>>>
>>> A) Remove all USING clauses from the request.
>>> B) Remove all USING NAMED clauses from the request.
>>> C) For each using-graph-uri=u in the protocol request
>>> For each INSERT/DELETE/INSERT DELETE operation in the request
>>> Add "USING u" to the operation
>>> D) For each using-named-graph-uri=u in the protocol request
>>> For each INSERT/DELETE/INSERT DELETE operation in the request
>>> Add "USING NAMED u" to the operation
>>>
>>>
>>> Protocol says nothing further about the semantics of these parameters --
>>> everything else is based on the semantics already given for USING and
>>> USING NAMED in SPARQL 1.1 Update. This includes things like whether
>>> "USING x" mentioned repeatedly in an update request refers to a mutable
>>> graph or a graph as retrieved from the Web; this includes things like
>>> the interaction between these parameters and WITH.
>>>
>>> Our options at this point:
>>>
>>> + Discuss any questions
>>> + Consider any alternative proposals
>>> + Consider dropping these parameters altogether
>>> + Consider adopting this proposal
>>
>> This does not address my concern that an update of several operations
>> may have different USING clauses in different operations. Overridding
>> any USING, and changing operations that don't mention USING, makes it,
>> to me, a different situation to query. The structure of the update
>> request is changed.
>
> I don't understand this concern; if you don't want to override them,
> then don't use this feature. Just because it can be misused doesn't mean
> it should be an error, right?

Because in a large request, it may be unclear that of the effect and the 
change in structure of the update request.  Consider where the update 
request chooses graphs known to be different in different operations.

	Andy

>
> Lee
>
>> Proposal: allow using-graph-uri and using-named-graph-uri in the
>> protocol if the operations of the request do not have any mention of
>> USING/USING NAMED. (A condition on uniform use of USING/USING NAMED
>> seems overly complicated.)
>>
>> Andy
>>
>>
>>
>>
>>
>
Received on Monday, 29 August 2011 17:23:29 GMT

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