W3C home > Mailing lists > Public > public-ldp-wg@w3.org > July 2014

Re: again with TurtlePatch

From: Andy Seaborne <andy@apache.org>
Date: Sun, 27 Jul 2014 18:40:46 +0100
Message-ID: <53D5399E.60408@apache.org>
To: Sandro Hawke <sandro@w3.org>, public-ldp-wg@w3.org
On 27/07/14 18:06, Sandro Hawke wrote:
> On 07/27/2014 12:33 PM, Sandro Hawke wrote:
>> On 07/27/2014 11:47 AM, Andy Seaborne wrote:
>>> On 27/07/14 16:12, Sandro Hawke wrote:
>>>> 1.  I realized allowing single-use blank nodes in the DELETE clause
>>>> gives us the wildcard functionality I really want, so I can say:
>>>>
>>>>    PREFIX x: <something...>
>>>>    DELETE DATA {
>>>>         x:me x:name []
>>>>    }
>>>>    INSERT DATA {
>>>>         x:me x:name "John Smith"
>>>>    }
>>>
>>> but it is then not SPARQL Update semantics.  You would need DELETE
>>> WHERE.
>>>
>>
>> Rats, I guess that's why I left it out earlier.   Thanks for the catch.
>>
>> I suppose we could add a WHERE clause that's restricted to containing
>> exactly the triples in the DELETE DATA clause which contain
>> variables.   I think that would do the right thing in SPARQL, and a
>> non-SPARQL processor could ignore it and treat variables as wildcards.
>>
>> So, that would make patches a little longer, and it would make the
>> syntax of the DELETE DATA clause be Turtle + ?variables, not just Turtle.
>>
>
> Double ARG -- I replied too quickly.   You were saying, I think, that I
> just need to use DELETE WHERE instead of DELETE DATA, not that I need a
> whole duplicate WHERE clause.

Yes, but

DELETE WHERE { x:me x:name ?var }

which is shorthand for

DELETE { x:me x:name ?var } WHERE { x:me x:name ?var }

No blank nodes allowed (because it's not a shorthand).

The cost of an update is in danger of being being opened up though.

(I'm not following closely enough but from what I can tell there are 
variations on the design requirements in the active threads, or at least 
different emphasises at different times.)

	Andy

>
> Thanks!!
>
>        -- Sandro
>
>
>>>     Andy
>>>
>>> PS Is human read/writeablity a requirement for LDP-Patch?
>>>
>>>
>>
>>
>> No, I don't think so.
>>
>>     -- Sandro
>>
>>
>>
>
Received on Sunday, 27 July 2014 17:41:16 UTC

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