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Re: in...of syntax Re: Turtle Last Call: Request for Review

From: Nathan <nathan@webr3.org>
Date: Tue, 31 Jul 2012 14:38:19 +0100
Message-ID: <5017DFCB.2040901@webr3.org>
To: Steve Harris <steve.harris@garlik.com>
CC: Jan Wielemaker <j.wielemaker@vu.nl>, Sandro Hawke <sandro@w3.org>, public-rdf-wg@w3.org
Steve Harris wrote:
> On 2012-07-31, at 13:58, Jan Wielemaker wrote:
> 
>> On 07/31/2012 02:42 PM, Steve Harris wrote:
>>> On 2012-07-31, at 13:28, Nathan wrote:
>>>
>>>> Steve Harris wrote:
>>>>> On 2012-07-31, at 02:36, Sandro Hawke wrote:
>>>>>> On 07/30/2012 06:37 PM, Andy Seaborne wrote:
>>>>>>>> BUt surely IF this is a good idea and worth having, which
>>>>>>>> Im assuming it is, then the longer we wait, the more
>>>>>>>> problems there will be with deployed systems out there
>>>>>>>> which don't support it. Kicking the can down the road is
>>>>>>>> not a good way to handle problems of legacy inertia.
>>>>>>>>
>>>>>>> Your argument would apply to literals-as-subjects as well;
>>>>>>> it's largely a syntax restriction.  If that's going to
>>>>>>> happen, it isn't in this WG (by charter), so why not make the
>>>>>>> changes in one step, not in multiple steps?
>>>>>> If literals-as-subject were primarily a matter of syntax, or
>>>>>> were seen as inevitable, I don't think they'd have been ruled
>>>>>> out by the charter.    I understand the reasons were mostly
>>>>>> about data structures and implementation techniques, but I
>>>>>> wasn't paying close attention to the technical content, so
>>>>>> perhaps I misunderstood.
>>>>> I think that the reason users don't try it is because of the
>>>>> syntax restriction, the reason engines don't (on the whole)
>>>>> support it is more due to the legacy of getting on for 15 years
>>>>> worth of software, research and publications. Knowing the that
>>>>> subject can only be a URI or bNode is a useful optimisation for
>>>>> many SPARQL engines.
>>>> wild idea and probably way off course - but what if there was some
>>>> kind of "EXTENDED MODE" keyword for sparql queries that let the
>>>> engine know to expect literals as subjects and other such things -
>>>> would an approach like that allow the engines to keep their
>>>> optimizations most of the time, and skip them when demanded?
>>> It would have to be at DB creation time (at least in 4/5store) as the
>>> optimisation goes right down into the storage engine.
>> I think that the more fundamental question is at the level of modelling.
>> My fear would be that we get triples that use proper names of entities
>> as subject instead of inventing a URI for this particular appearance of
>> the string.  If this happens we introduce massive ambiguity (or conflicts, depending on your viewpoint).  Next is
>>
>> "Beer" "sub type of" "Animal".
>>
>> URI's have a role: they avoid ambiguity and they can be used to fetch
>> data as Open Linked Data.  They are not without problems, but they do
>> fix some problems associated with natural language words.
>>
>> In any case, the order must be to make a decision at the datamodel first
>> and next at the syntax level.  Please don't 
> 
> That's a very good point.
> 
> People coming from a relational database background will definitely use integer "keys", until they (hopefully) realise why that's a bad idea on the web. e.g.
> 
> 9876435 a :Product ;
>         :name "5cm Trunion (Foo Inc.)" ;
>         :cost 12.99 ;

people will often use integer "keys", and often do even in linked data, 
by using (inverse) functional properties, or by prefixing part of a URI 
before the key.

> To a Linked Data person that's very clearly a bad idea, but it's an obvious, and rational translation from a database table.

I have to disagree (not to be argumentative or negative though!) - it 
seems like a rational idea to me, to use integer keys, even better to 
namespace them within a URI (http://example.org/products/9876435), and 
to have optimizations of integer only keys within a storage engine for a 
specific domain.

That's not the point though, the point is that the above "looks like 
RDF", "is N3", but isn't "linked data" - as it's not linked. It's not a 
bad idea, it's just not linked data.

Use URIs as names is the first principal of linked data, simple 
education gets that across to people.

The above looks like a set of three useful triples to me, that I could 
use in multiple scenario. RDF doesn't support it it over the wire, and 
of course it isn't linked - doesn't make it unwanted, bad, or useless 
though.

I'm aware it's way too late to see literals as subjects in RDF 1.1, but 
will defend their usage and the idea of them, as it's certainly not 
useless, stupid, or bad; nor something to create fear, uncertainty, and 
doubt over. They have some value, some cost, some people would like 
them, some people would not.

Best,

Nathan
Received on Tuesday, 31 July 2012 13:39:25 GMT

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