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Re: [Fwd: SPARQL Protocol Review and Comments]

From: David Wood <dwood@softwarememetics.com>
Date: Wed, 4 Jan 2006 15:01:58 -0500
Message-Id: <FB1F8574-E091-4544-9D52-B385EB4F64C8@softwarememetics.com>
Cc: Dan Connolly <connolly@w3.org>, public-rdf-dawg-comments@w3.org
To: Kendall Clark <kendall@monkeyfist.com>

On 4 Jan2006, at 14:47, Kendall Clark wrote:
> On Jan 4, 2006, at 2:03 PM, David Wood wrote:
>>>>   OMISSION: In the "Malformed Query" paragraph of Section 2.1.4,  
>>>> it is unclear what behavior is expected from a query processing  
>>>> service if a malformed query does not result in a MalformedQuery  
>>>> fault.  One way to solve this is to make such a fault mandatory  
>>>> ("must" instead of "should").  If that is not done, the document  
>>>> should say what kind of behavior to expect (is a  
>>>> QueryRequestRefused OK?  How about returning nothing?).
>>>
>>> The WG explicitly decided to make MalformedQuery optional. I'm  
>>> not clear why you think the document must say what must happen in  
>>> the case where the spec says an implementation may do something  
>>> or may not. Can you say more about this?
>>
>> Well, an implementor will have to make exactly that decision.   
>> Either they will choose to implement MalformedQuery or they  
>> won't.  If they don't, then what should they do?  Return nothing?   
>> Drop the connection?  QueryRequestRefused?  As an implementor, I'd  
>> be looking first to the spec for guidance.  Failing to find any,  
>> I'd do what I thought best - which is another way of saying that  
>> I'd make a different decision to someone else and hence  
>> potentially cause an interoperability problem.
>
> The WG discussed explicitly the case of requiring a service to  
> always return MalformedQuery in cases where the query string isn't  
> legal SPARQL. It didn't choose to specify that design.
>
> In some cases an illegal SPARQL query will be *answered* --  
> because, say, some service implements a superset of SPARQL that  
> includes, say, some syntactic no-no. Thus, the cases seem to be:
>
> 1. answer illegal SPARQL queries with some results
> 2. return MalformedQuery
> 3. the spec doesn't say what to do otherwise
>
> I believe that's the design that spec describes and that the WG  
> consents to.
>
> Do you have some suggested text to make this clearer? (I think  
> there was some desire not to explicitly say (1)... :>)

I don't like that decision, but nobody said I was expected to :)

I gave some thought to adding some explanatory text to Section 2.1.4,  
but gave up.  Instead, I believe that the current use of the word  
'should' correctly states the WG's position.

Regards,
Dave
Received on Wednesday, 4 January 2006 20:02:01 GMT

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