Re: Generic Property-Value Proposal for Schema.org

On 5/3/2014 4:10, Niklas Lindström wrote:
> My opinion, based on experience in both consuming data and working to 
> unify disparate descriptions, is that, in the general case of needing 
> specific properties beyond the core or schema.org <http://schema.org>, 
> it would be quite valuable to apply the existing mechanism of mixing 
> vocabularies, native to RDF and the enabler of decentralized 
> vocabulary growth. It has been there from the start and proven 
> extremely valuable in specific data integration scenarios.

+1

I believe Martin has raised a very important topic - on how to make it 
easier for site owners to publish data for which no fixed schema.org 
extension already exists. Another important topic in his proposal is the 
handling of units and ranges. But I believe neither of these necessarily 
require yet another extension mechanism, especially if this extension 
mechanism breaks the integrity and simplicity of the original data model 
and its mapping to triples.

URI-based property definitions similar to RDF/OWL can already be used, 
and anyone can very easily create their own property my:property. If 
microdata has a problem with that because it is optimized for a single 
namespace then the extension should be defined for microdata *syntax* 
only, but not for the general schema.org *data model*.

On the topic of units and ranges, I see no reason why these should only 
apply to "additional" properties. They make a lot of sense for existing 
schema.org types too, such as schema:height should also be able to have 
values such as "10 - 500 cm". So this problem should be addressed 
separately.

I believe the original issue of making it easier for site owners to 
publish data could be addressed by preparing suitable documentation and 
quick start guides with the recommended design patterns. If 
additionalProperty is still needed, then please only for microdata syntax.

Holger