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Re: Cardinality of schema.org properties

From: Dan Brickley <danbri@danbri.org>
Date: Thu, 20 Oct 2011 07:32:59 +0200
Message-ID: <CAFNgM+YqEtCp6=X1rkbtQ56+RTe__BsYNUP0zJM6MqzgLbr5kA@mail.gmail.com>
To: John Panzer <jpanzer@google.com>
Cc: public-vocabs <public-vocabs@w3.org>
On 20 October 2011 01:22, John Panzer <jpanzer@google.com> wrote:
> I'm trying to determine how to know what the intended cardinality of any
> given schema.org defined property.
> Some (such as "name" and "url") appear to be defined in English as appearing
> at most once.  Semantically, having them appear multiple times would appear
> problematic.
> Some, such as "tracks", appear to be explicitly defined as multivalued and
> indeed need an ordering (see
> also http://lists.w3.org/Archives/Public/public-html-data-tf/2011Oct/0004.html).
> Is this a correct interpretation?  How would one determine whether something
> is potentially multivalued or not based on the spec?

In http://schema.org/docs/extension.html it is explicitly linked to
natural language plurality, as you suggest:

"Note on naming conventions
Schema.org uses the following naming convention. We request that you
follow this naming convention for your extensions as well.
Types and Enumerations start with a capital letter and are CamelCase.
Properties start with a lower case letter and are also camelCase.
Properties that can take multiple values (such as parents) are plural
and those that can take only a single value (such as dateOfBirth) are

Looking at http://schema.org/MusicPlaylist
http://schema.org/MusicRecording and nearby, it could certainly be
clearer about ordering. Investigating...

Received on Thursday, 20 October 2011 05:33:27 UTC

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