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Re: Multiple types from different vocabularies (ACTION-7)

From: Martin Hepp <martin.hepp@ebusiness-unibw.org>
Date: Tue, 18 Oct 2011 22:17:49 +0200
Cc: public-html-data-tf@w3.org
Message-Id: <7B0D473D-B7C1-4CF0-B76A-B05308374470@ebusiness-unibw.org>
To: Jeni Tennison <jeni@jenitennison.com>
Hi Jeni,
On Oct 15, 2011, at 9:57 PM, Jeni Tennison wrote:

> Martin,
> On 15 Oct 2011, at 19:49, Martin Hepp wrote:
>> My take is that if schema.org defines the property "secondaryType" for http://schema.org/Thing, this will be sufficient for 99 % of the cases. After all, schema.org is the only major Microdata vocabulary out there (IMHO).
> Guha's indicated that he's in favour of schema.org defining the http://schema.org/type. Are you happy with this as a way forward?

Yes, as long as this is also added to http://schema.org/Thing so that you can use it everywhere. It would be fully sufficient to use my GoodRelations extensions

    http://purl.org/vso/ns (Vehicles)
    http://purl.org/tio/ns (Tickets for events, locations, and transportation)
    http://purl.org/coo/ns (Car configuration)


    http://www.productontology.org (300,000 product types based on Wikipedia)

in combination with schema.org.

>>> The first is that it would mean adding this property to existing vocabularies to make them microdata ready. You could argue that to use existing RDF vocabularies in microdata you have to do some extra work anyway (as Hixie has pointed out, you can't just port them because there are extra semantics you have to define for microdata use), so adding another property isn't a big deal, but some vocabularies may be very hard to change.
>> I would be interested to learn what those are. IMO, the only really important thing you need is to define, in plain English, how URIs for properties should be formed 
>> a)base URI + local name or 
>> b) URI of the itemtype + local name of the property.
>> This is at least the approach we take with GoodRelations. Did I overlook anything?
> In recent mails, Hixie said [1]:
>> Incidentally, note that you can't just take, say, an RDF vocabulary, or a Microformats vocabulary, and just use it in microdata directly. A microdata vocabulary has to define processing rules that are often not provided for RDF and Microformats vocabularies, and has to use the terms defined in the HTML specification to describe how the terms work. You can see examples of how to define vocabularies in the HTML standard:


I will have a look at that and provide the respective definitions etc. for GoodRelations.

However, as far as I know, there is no public documentation of this kind for schema.org itself, or did I miss anything?

If anyone has a pointer, I would be happy to learn of it.

> You know it would be really great to use GoodRelations as an example of an RDF vocabulary being adapted so that it can also be used with microdata, showing the steps that need to be taken by vocabulary authors to port existing RDF schemas. Could I persuade you to put together a description of what you've had to do on the wiki page at [3]? (We might perhaps extend that to show use with microformats-2 if we were feeling ambitious.)

I will try, but getting the work done and deployed is more important now, so I cannot promise anything. There will be a full documentation with pointers at


Currently, we just specify how property URIs are being formed.
Received on Tuesday, 18 October 2011 20:18:26 GMT

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