Re: Last Call for Comments ... Re: proposal for updates to http://schema.org/Event

On Wed, Feb 29, 2012 at 11:50 AM, Dan Brickley <danbri@danbri.org> wrote:

> On 24 February 2012 16:39, Dan Brickley <danbri@danbri.org> wrote:
> > I've just posted another draft proposal in the W3C wiki,
> > http://www.w3.org/wiki/EventSchemaUpdate
> >
> > From the wrapper text there,
> >
> > "The proposal comes from the Google teams working with the existing
> > Event markup, and has been checked by the other schema.org partners
> > prior to publication. See PDF for full details of the proposal."
> >
> > * "Proposes 3 new properties of Event: eventStatus, previousStartDate,
> > previousEndDate to support canceled or rescheduled events.
> > * Adds eventCategory to support categorised events.
> > * Supports recurring events by making startDate and endDate repeated.
> > * Encourages use of existing 'url' property (of Thing) to link to
> > associated Web pages."
>

I think this last one is worth highlighting for broader discussion too.  As
I understand it, the question is about whether a) Thing/url is the identity
of the item (equivalent to itemid and conceptually akin to rel=canonical
for that specific item) or whether b) it's ok for Thing/url to point to any
URL that represents the same real-world entity, even if it's a different
manifestation (e.g., someone else's database record for that entity).

My understanding has been a) (equivalent to itemid), and that Thing/url was
provided mostly as a convenience for being able to markup existing anchor
tags without having to repeat the URL in the page markup (which itemid
requires).

However, accepting the proposed change would effectively eliminate option
a) and mean that Thing/url was instead meant to express equivalence rather
than identity.  This would also mean that itemids (rather than Thing/url)
would have to be declared in order to link schema.org objects (meaning
specifying objects as values by reference rather than nesting them).

The alternative, as stated in the doc, is to create Thing/sameAs for these
equivalence use cases.  I personally prefer that option.

-jason