Re: Schema.org properties having a collection as value and hydra:Collection

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Am 10.10.2014 10:31, schrieb ☮ elf Pavlik ☮:
> On 10/10/2014 09:52 AM, Dietrich Schulten wrote:
>> Hi elf,
> Hi Dietrich :)
> 
>> 
>> comments inline.
>> 
>> Am 09.10.2014 09:33, schrieb ☮ elf Pavlik ☮:
>>> On 10/09/2014 07:17 AM, Dietrich Schulten wrote:
>>>> Properties like schema:review allow list or single values,
>>>> but normally that is represented by an item of the target
>>>> type or an array thereof. If I make the value of review a
>>>> link, it seems perfectly okay if the link dereferences a
>>>> Review or a Review[]. But can it point to a
>>>> hydra:Collection?
>>> have your read
>>> https://github.com/HydraCG/Specifications/issues/41 ?
>> 
>> I did and from my understanding, the discussion seemed related to
>> my question but there was no agreement about the solution yet. I
>> am not well versed with turtle and rdf, too, so I must admit I
>> struggle to follow the discussion there. At hydra-cg people with
>> ReST and RDF background must learn to communicate somehow :)
> I believe we can do it :)
> 
> Still IMO you may want to have decent understanding of RDF
> *especially* if you want to participate in Hydra standardization
> work. I recommend starting with
> http://www.w3.org/TR/2014/NOTE-rdf11-primer-20140624/

Fair enough. I did read the primer a while ago, when I became
interested in json-ld :) But this is advanced stuff, as it seems.

> In RDF (not only schema.org vocab) when you have subject -
> predicate - object by default you can make any number of of
> statements using different objects for the same subject - predicate
> pair. So in JSON-LD each property can accept either array or single
> object.
> 
> Now let's take your example to JSON-LD playground:
> http://bit.ly/1tgYc73
> 
> As you see according to specified context "hydra:member" extends
> to "http://www.w3.org/ns/hydra/core#member" and to my understanding
> has completely nothing to do with 
> "http://api.example.com/products/1/reviews#hydra:member"

After looking at the use of fragment identifiers in the hydra vocab,
it seems a url with fragment identifier points to an object having an
@id with exactly that url with fragment identifier somewhere in a
surrounding object identified by the url without fragment identifier.

So the problem seems to be that the array of reviews has no
identifier, for RDF the array is simply not there, rather it sees
repeated triples of
/products/1/reviews - member - review/1
/products/1/reviews - member - review/2


> 
> Have you had chance to read http://www.w3.org/TR/webarch/ which
> explains topics like URI Opacity?

Yes. Do you think I violated opacity here?



- -- 
Dietrich Schulten
Escalon System-Entwicklung
Bubenhalde 10
74199 Untergruppenbach
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Received on Friday, 10 October 2014 10:15:51 UTC