One other issue to bear in mind: it's *simple* to have properties as a
separate thing. I have been following this discussion with some
interest but... well, I don't think I'm particularly stupid, but most
of it is completely above my head.

Saying "here are items, here are a set of properties you can define
relating to them, here's some notes on how to use properties" is going
to get a lot more people able to contribute than if they need to start
understanding theoretical aspects of semantic relationships...

;-)

Andrew.

On 28 May 2014 09:37, Daniel Kinzler <daniel.kinzler@wikimedia.de> wrote:
> Key differences between Properties and Items:
>
> * Properties have a data type, items don't.
> * Items have sitelinks, Properties don't.
> * Items have Statements, Properties will support Claims (without sources).
>
> The software needs these constraints/guarantees to be able to take shortcuts,
> provide specialized UI and API functionality, etc.
>
> Yes, it would be possible to use items as properties instead of having a
> separate entity type. But they are structurally and functionally different, so
> it makes sense to have a strict separate. This makes a lot of things easier, e.g.:
>
> * setting different permissions for properties
> * mapping to rdf vocabularies
>
> More fundamentally, they are semantically different: an item describes a concept
> in "the real world", while a property is a structural component used for such a
> description.
>
> Yes, properies are simmilar to data items, and in some cases, there may be an
> item representing the same concept that is represented by a property entity. I
> don't see why that is a problem, while I can see a lot of confusion arising from
> mixing them.
>
> -- daniel
>
>
> Am 28.05.2014 09:25, schrieb David Cuenca:
>> Since the very beginning I have kept myself busy with properties, thinking about
>> which ones fit, which ones are missing to better describe reality, how integrate
>> into the ones that we have. The thing is that the more I work with them, the
>> less difference I see with normal items.... and if soon there will be statements
>> allowed in property pages, the difference will blur even more.
>> I can understand that from the software development point of view it might make
>> sense to have a clear difference. Or for the community to get a deeper
>> understanding of the underlying concepts represented by words.
>>
>> But semantically I see no difference between:
>> cement (Q45190) <emissivity (P1295)> 0.54
>> and
>> cement (Q45190) <emissivity (Q899670)> 0.54
>>
>> Am I missing something here? Are properties really needed or are we adding
>> unnecessary artificial constraints?
>>
>> Cheers,
>> Micru
>>
>>
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>
>
> --
> Daniel Kinzler
> Senior Software Developer
>
> Wikimedia Deutschland
> Gesellschaft zur Förderung Freien Wissens e.V.
>
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--
- Andrew Gray
  andrew.gray@dunelm.org.uk

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