W3C home > Mailing lists > Public > public-hydra@w3.org > June 2014

Re: How to avoid that collections "break" relationships (ISSUE-41)

From: Gregg Kellogg <gregg@greggkellogg.net>
Date: Thu, 12 Jun 2014 16:24:07 -0700
Cc: public-hydra@w3.org
Message-Id: <9A47F125-5987-4F3F-A036-B45E69A6B7BB@greggkellogg.net>
To: Markus Lanthaler <markus.lanthaler@gmx.net>
On Jun 12, 2014, at 3:14 PM, Markus Lanthaler <markus.lanthaler@gmx.net> wrote:

> Hi Pavlik,
> 
> On 11 Jun 2014 at 22:06, ☮ elf Pavlik ☮ wrote:
>> Great to see you working hard on addressing what seems like a very
>> common problem!
>> 
>> On 06/11/2014 12:11 AM, Markus Lanthaler wrote:
>>>>> PS I don't feel as strongly about this particular issue as some
>>>>> e-mails seem to indicate; I just want to help ensure that we pick the
>>>>> right names for terms.
>>> 
>>> Better to get this right now as otherwise we have to live with it forever.
>>> So thanks for bringing in other perspectives to look at these things.
>> 
>> I tried to follow this thread but you may think bit to fast for me ;)
> 
> :-) But honestly, kudos for letting us know.
> 
> 
>> I understand that you have found a preffered pattern for implementing it
>> and now try to pick terms which will help expressing it in the most
>> clear way?
> 
> Exactly.
> 
> 
>> I guess you could have lost few other people during this mental sprint.
>> Could you imagine clearly restating current direction and invite more
>> people to give feedback on choosing particular terms?
> 
> Sure. I just created a Wiki page summarizing the current state of affairs:
> 
>  https://www.w3.org/community/hydra/wiki/Collection_Design
> 
> Hope this helps. If not, please let me know.
> 
> 
>> I also don't really understand how this thread relates to parallel one
>> on schema.org mailing list around ItemList
>> http://lists.w3.org/Archives/Public/public-vocabs/2014Jun/0121.html
> 
> To be honest, I'm not completely sure either. I asked a couple of months ago if ItemList could be used for something like this and how ItemList is intended to be used. I was told (by Jason from Google) the following:
> 
>    "I appreciate re-using an existing Class, but I think ItemList was
>     intended for a different use case than collections (I've given
>     the same feedback to Sam).  It's a subclass of CreativeWork
>     because it's for "editorialized" lists (top 10 list, playlists,
>     etc.). I think we need something new like an actual Collection
>     class in schema.org"
> 
>     [http://lists.w3.org/Archives/Public/public-hydra/2014Mar/0128.html]

The proposed update to ItemList <http://sdo-wip1.appspot.com/ItemList> makes them more generally useful, although it's still a kind of CreativeWork.

You can now have items be Things in addition to Text. This includes a new ListItem, which allows items to be ordered with position, previous and next. No support for paging, other than to have a ListItem who's item is an ItemList, but that's not to satisfying.

In any case, the collection mechanism is more than just a way of referencing specific members, but also associating a relationship between a subject and object, which is no-where to be seen in any ListItem proposal. I am concerned that those of us using both schema.org and Hydra will have some difficult decisions on how to separate an entity's definition between multiple resources other than relying exclusively on reverse relationships, and that still doesn't handle wide many-to-many relationships such as Friend or Follows.

Gregg

> Once we are happy with the Collection design we could try to propose it for inclusion into Schema.org.
> 
> 
>> Oh, since LDP Container got mentioned in some previous conversation
>> maybe also worth adding a comment to the wiki with short comparison of
>> design choices?
> 
> AFAICT, LDP hasn't finalized their design yet (especially paging is still very much in flux). Furthermore, their containers enforce specific interaction models which turns it into a completely different design. I didn't add anything to the wiki, but feel free to start a new thread here on the list if you want to discuss this further.
> 
> 
>> Please don't let me slow you down with those suggestions/request, just
>> wanted say that now everyone may find capacity to keep up with your pace
>> :runner:
>> 
>> Keep up the good work!
> 
> I very appreciate that you "stepped in". The goal of this group should be to be as inclusive as possible. We are a quite interesting group as we have members with very very different backgrounds. This might make collaboration a bit more challenging from time to time but it is really a Good Thing™ :-) It ensures that we design a solid solution.
> 
> 
> Cheers,
> Markus
> 
> 
> --
> Markus Lanthaler
> @markuslanthaler
> 
> 
Received on Thursday, 12 June 2014 23:24:38 UTC

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