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Re: Generic Property-Value Proposal for Schema.org

From: Francois-Paul Servant <francoispaulservant@gmail.com>
Date: Sat, 3 May 2014 02:49:48 +0200
Cc: Thad Guidry <thadguidry@gmail.com>, W3C Web Schemas Task Force <public-vocabs@w3.org>
Message-Id: <450B435D-E83A-4700-A001-692978367A52@gmail.com>
To: "martin.hepp@ebusiness-unibw.org" <martin.hepp@ebusiness-unibw.org>
Martin,

I have 2 problems with your answer.

1)
You explain that we cannot infer that the PropertyValue (itemId "data") is of type GearboxTypeValue - OK
But that's not what I asked: 

>> if propertyID is the URI of a property, then the value of the "value property" is of type in the range of propertyID

So, from this:

> 	  <link itemprop="value" href="http://purl.org/vvo/ns#GearboxDSG" />VW DSG
> 	  <link itemprop="propertyID" href="http://purl.org/vvo/ns#gearbox" />

am I correct in deducing that the type of http://purl.org/vvo/ns#GearboxDSG is in the range of http://purl.org/vvo/ns#gearbox?

This is not stated in the documentation about propertyID, but I think it could (and should).

2)
Now, in the general case of PropertyValue, I understand that formally  the PropertyValue and the value are 2 different things (cf MartinHeppThePerson and MartinHeppAsAPropertyValue in an earlier message). But in the case of product features, I see no harm in saying that a feature is a PropertyValue:

<div itemtype="http://schema.org/Car" itemid="car">
 <img itemprop="image" src="station_waggon123.jpg" />
 <span itemprop="name">Station Waggon 123</span>
 <div itemprop="feature" itemscope itemtype="http://schema.org/Feature" itemid="http://purl.org/vvo/ns#GearboxDSG">
	  <span itemprop="propertyName">Gearbox Type</span>:
	  <span itemprop="name">VW DSG</span>:
	  <link itemprop="propertyID" href="http://purl.org/vvo/ns#gearbox" />
 </div>  
</div>

Same number of lines as in your code, but one resource less. You can be sure that people will be at least disoriented if there are 2 distinct resources for almost the same thing.

BTW, we could save one line:

<div itemtype="http://schema.org/Car" itemid="car">
 <img itemprop="image" src="station_waggon123.jpg" />
 <span itemprop="name">Station Waggon 123</span>
 <div itemprop="feature" itemscope itemtype="http://purl.org/vvo/ns#GearboxTypeValue" itemid="http://purl.org/vvo/ns#GearboxDSG">
	  <span itemprop="propertyName">Gearbox Type</span>:
	  <span itemprop="name">VW DSG</span>:
 </div>  
</div>

The data that we publish at Renault looks like this

fps

Le 3 mai 2014 à 01:50, "martin.hepp@ebusiness-unibw.org" <martin.hepp@ebusiness-unibw.org> a écrit :

> Actually, no - I may have been unclear, but you are mixing the markup data with data that you can derive from the markup data.
> 
> Using propertyID with the URI of a Web vocabulary does not imply that the value entity has the type defined as the range for that property.
> 
>> 
>> here, propertyID points to http://purl.org/vvo/ns#gearbox, which clearly identifies the property "have gearbox type", whose range is http://purl.org/vvo/ns#GearboxTypeValue (which could be very be passed in the itemtype in addition to or in place of http://schema.org/PropertyValue)
> 
> <div itemtype="http://schema.org/Car" itemid="car">
>  <img itemprop="image" src="station_waggon123.jpg" />
>  <span itemprop="name">Station Waggon 123</span>
>  <div itemprop="additionalProperty" itemscope itemtype="http://schema.org/PropertyValue" itemid="data">
> 	  <span itemprop="name">Gearbox Type</span>:
> 	  <link itemprop="value" href="http://purl.org/vvo/ns#GearboxDSG" />VW DSG
> 	  <link itemprop="propertyID" href="http://purl.org/vvo/ns#gearbox" />
>  </div>  
> </div>
> 
> does not (formally) imply that the http://schema.org/PropertyValue node is also of the type http://purl.org/vvo/ns#GearboxTypeValue.
> 
> You can of course write a heuristic, e.g. as a SPARQL CONSTRUCT rule that say that if you find the above structure, then you should translate this to
> 
>    :car <http://purl.org/vvo/ns#gearbox> http://purl.org/vvo/ns#GearboxDSG .
> 
> But the PropertyValue is not directly that entity. 
> 
> So it would not be correct to infer
> 
>    :data rdf:type http://purl.org/vvo/ns#GearboxTypeValue.
> 
> Because http://purl.org/vvo/ns#GearboxTypeValue is the type for http://purl.org/vvo/ns#GearboxDSG, but not for the PropertyValue entity :data.
> 
> Martin
> 
> On 03 May 2014, at 01:16, Francois-Paul Servant <francoispaulservant@gmail.com> wrote:
> 
>> Hi Martin,
>> 
>> Le 3 mai 2014 à 00:02, martin.hepp@ebusiness-unibw.org a écrit :
>> 
>>> Dear Francois-Paul:
>>> On 01 May 2014, at 19:24, Francois-Paul Servant <francoispaulservant@gmail.com> wrote:
>>> 
>>>> Thad,
>>>> 
>>>> not sure to fully understand you here.
>>>>> does propertyID always infer the idea of a Kind or Type ?
>>>> I'd say that if propertyID is the URI of a property, then the "idea of a Kind or Type" you mention would be the range of the property in question.
>>>> 
>>> 
>>> 
>>> No, propertyID can be
>>> 
>>> a) a prefixed string, mainly meant to standards for product properties, like eClass;
>>> b) a site-specific, non-prefixed string (e.g. the primary key of the property, the vendor-specific id of the property. For instance, in some Volkswagen systems, the property "upholstery" has the ID "4", see http://www.volkswagen.co.uk/vocabularies/vvo/ns#Upholstery.
>>> c) a URI or URL indicating the type of the property.
>>> 
>>> So c) can be a URI of a class in a proper Linked Open Data Vocabulary, but it could also be the fragment URI of an entry in a car maker's glossary page.
>> 
>> there's something that I do not understand, or a possible ambiguity, with c)
>> in your reply to your my first email, you give an example (and I was very happy with it):
>> 
>> <div itemtype="http://schema.org/Car
>> ">
>>  <img itemprop="image" src="station_waggon123.jpg" />
>>  <span itemprop="name">Station Waggon 123</span>
>>  <div itemprop="additionalProperty" itemscope itemtype="
>> http://schema.org/PropertyValue
>> ">
>> 	  <span itemprop="name">Gearbox Type</span>:
>> 	  <link itemprop="value" href="
>> http://purl.org/vvo/ns#GearboxDSG
>> " />VW DSG
>> 	  <link itemprop="propertyID" href="
>> http://purl.org/vvo/ns#gearbox
>> " />
>>  </div>  
>> </div>
>> 
>> here, propertyID points to http://purl.org/vvo/ns#gearbox, which clearly identifies the property "have gearbox type", whose range is http://purl.org/vvo/ns#GearboxTypeValue (which could be very be passed in the itemtype in addition to or in place of http://schema.org/PropertyValue)
>> 
>> so, I read this as: c) a URI or URL that identifies the property
>> 
>> from this, we could infer
>> s http://purl.org/vvo/ns#GearboxTypeValue http://purl.org/vvo/ns#GearboxDSG
>> 
>> if we have
>> s additionalProperty [value o ; propertyId p]
>> then
>> s p o.
>> 
>> So, do you confirm that you answer "No" when I say 
>> if propertyID is the URI of a property, then the value of the "value property" is of type in the range of propertyID
>> 
>> fps
>> 
>>> 
>>> I do not want to revive the discussion whether using URIs of "pages" as proxies for entities in the context of schema.org is good or bad, but I think this should be allowed.
>>> 
>>> 
>>> Martin
>>> 
>>> 
>>>> fps
>>>> 
>>>> Le 1 mai 2014 à 18:22, Thad Guidry <thadguidry@gmail.com> a écrit :
>>>> 
>>>>> Francois, Martin,
>>>>> 
>>>>> Is that the intended use for propertyID ?  I did not get the feeling from looking through the proposal that it could also be used to hold Kinds, Types, Contexts, etc.  I instead got the feeling that it was to be used for identifiers... ah looking at it again... now I see... so ... what is the eClass representation of this in reality ?
>>>>> 
>>>>> <meta itemprop="propertyID" content="eclass81:02-AAM226">
>>>>> 
>>>>> is that content equate to some Kind or Type ? ... does propertyID always infer the idea of a Kind or Type ?  if not, ... how does one infer a Kind or Type in Martins proposal ?
>>>>> 
>>>>> 
>>>>> I have a box...that has  "some KIND of Feature" ... how do I express that Feature KIND...that many of my boxes would share ?  Is that what propertyID would be used for ?
>>>>> 
>>>>> (I must be really tired today)
>>>>> 
>>>>> 
>>>>> 
>>>>> On Thu, May 1, 2014 at 11:14 AM, Francois-Paul Servant <francoispaulservant@gmail.com> wrote:
>>>>> Thad,
>>>>> 
>>>>> I've been very fast in my explanation.
>>>>> Whatever the interpretation of PropertyValue, we can write:
>>>>> 
>>>>> foo:YourBook schema:additionalProperty x:MartinHeppAsPV.
>>>>> x:MartinHeppAsPV a PropertyValue;
>>>>> 	propertyID author;
>>>>> 	value x:MartinHeppThePerson
>>>>> 
>>>>> but x:MartinHeppThePerson and x:MartinHeppAsPV are not the same thing.
>>>>> 
>>>>> Must I say that I strongly support Martin's proposal direction? My only concern is the following: it must allow to use a URI for the object of the property (the "feature") when we have one, (and minting one should be encouraged otherwise), because this allows to publish data as they are, and to lift them later.
>>>>> 
>>>>> Best,
>>>>> 
>>>>> fps
>>>>> 
>>>>> Le 1 mai 2014 à 16:53, Thad Guidry <thadguidry@gmail.com> a écrit :
>>>>> 
>>>>>> Francois,
>>>>>> 
>>>>>> That's because this:
>>>>>> 
>>>>>> foo:YourBook schema:additionalProperty x:MartinHeppThePerson.
>>>>>> 
>>>>>> is missing the sub-property for the right context... I.E.  it's missing the word "author"
>>>>>> 
>>>>>> 1. perhaps that missing context needs to somehow use "additionalType" ?
>>>>>> 
>>>>>> 2. maybe context should just be the "scope" of the Property-Value pairing?
>>>>>> 
>>>>>> In Schema.org .. Contexts and Kinds are referred to and modeled actually as Types. ..(well, that's how we CURRENTLY have Schema.org designed).
>>>>>> 
>>>>>> But Martin's proposal presents a slight variation on the CURRENT Design...that we need, but that we need to get right...and it can be a work in progress starting at Products & Places. Agreed.
>>>>>> 
>>>>>> Martin,
>>>>>> 
>>>>>> The new proposal looks fine to me... just wondering about how to handle missing Context, as Francois is hitting upon...would that be through the use of "additionalType" or "scope" or something else ?  Can you mock up an example for his Sunroof case ?
>>>>>> 
>>>>>> -- 
>>>>>> -Thad
>>>>>> +ThadGuidry
>>>>>> Thad on LinkedIn
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> -- 
>>>>> -Thad
>>>>> +ThadGuidry
>>>>> Thad on LinkedIn
>>>> 
>>> 
>>> 
>> 
> 
> 
Received on Saturday, 3 May 2014 00:50:16 UTC

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