- From: John Walker <john.walker@semaku.com>
- Date: Fri, 20 Mar 2015 09:21:38 +0100 (CET)
- To: W3C Vocabularies <public-vocabs@w3.org>, Guha <guha@google.com>
- Cc: Sandro Hawke <sandro@w3.org>, Ralph Swick <swick@w3.org>, Tim Berners-Lee <timbl@w3.org>
- Message-ID: <878334684.395093.1426839698928.open-xchange@oxweb03.eigbox.net>
Hi Guha,
I have a few questions/thoughts around the proposal that every item in the core
would also be in every extension.
Would this apply only to the reviewed extensions only, or also to external
extensions?
I can understand that only using terms from a single prefix lowers the bar for
getting started, but I don't think it's too tricky to get your head round using
multiple prefixes in any of the syntaxes (although some are easier than others).
IMHO it would be simpler and more understandable to have a single identifier
(URL/URI/IRI) for each term/item rather than multiple aliases.
(This however would not preclude that two different extensions might have a
different term/item for a very similar concept and hence each has own
identifier)
Also I expect many practical use cases where users need to mix'n'match terms
from different extensions.
For example the GS1 extension would have many terms for general use and
hopefully enough to cover some specific domains like food and beverage, but may
not fully cover other domains like consumer electronics.
Admittedly this will not be needed in all cases, but I think there are enough to
warrant giving it some deep thought (i.e. it is far from a corner case).
Regards,
John Walker
Principal Consultant & co-founder
Semaku B.V.
SFJ 4.009, Torenallee 20, 5617 BC Eindhoven
Mobile: +31 6 475 22030
Email: john.walker@semaku.com
Skype: jaw111
KvK: 58031405
BTW: NL852842156B01
IBAN: NL94 INGB 0008 3219 95
> On March 20, 2015 at 12:36 AM Guha <guha@google.com> wrote:
>
> The various discussions around this extension proposal seem to have reached
> quiescence. I am hoping this is more because the questions were answered than
> because of boredom.
>
> We would like to proceed with the implementation of this proposal. If there
> are strong objections, now would be the right time to raise them.
>
> guha
>
> On Fri, Feb 13, 2015 at 1:34 PM, Guha <guha@google.com
> <mailto:guha@google.com> > wrote:
> > >
> > Schema.org extension mechanism
> >
> >
> > Motivation
> > As<http://schema.org> adoption has grown, a number groups with more
> > specialized vocabularies have expressed interest in
> > extending<http://schema.org> with their terms. The most prominent example of
> > this is GS1 with product vocabularies. Other examples include real estate,
> > medical and bibliographic information. Even in something as common as human
> > names, there are groups interested creating the vocabulary for representing
> > all the intricacies of names.
> >
> > Outline of solution
> >
> > There are two kinds of extensions: reviewed extensions and external
> > extensions. Both kinds of extensions typically add subclasses and properties
> > to the core. Properties may be added to existing and/or new classes. More
> > generally, they are an overlay on top of the core, and so they may add
> > domains/ranges, superclasses, etc. as well. Extensions have to be consistent
> > with the core<http://schema.org> . Every item in the core (i.e.,
> > www.schema.org <http://www.schema.org> ) is also in every extension.
> > Extensions might overlap with each other in concepts (e.g., two extensions
> > defining terms for financial institutions, one calling it FinancialBank and
> > other calling it FinancialInstitution), but we should not have the same term
> > being reused to mean something completely different (e.g., we should not
> > have two extensions, one using Bank to mean river bank and the other using
> > Bank to mean financial institution).
> >
> > Reviewed Extensions
> > Each reviewed extension (say, e1), gets its own chunk
> > of<http://schema.org> namespace:<http://e1.schema.org> . The items in that
> > extension are created and maintained by the creators of that extension.
> > Reviewed extensions are very different from proposals. A proposal, if
> > accepted, with modifications could either go into the core or become a
> > reviewed extension.
> >
> > A reviewed extension is something that has been looked at and discussed
> > by the community, albeit not as much as something in the core. We also
> > expect a reviewed extension to have strong community support, preferably in
> > the form of a few deployments.
> >
> > External Extensions
> > Sometimes there might be a need for a third party (such as an app
> > developer) to create extensions specific to their application. For example,
> > Pinterest might want to extend the<http://schema.org> concept of ‘Sharing’
> > with ‘Pinning’. In such a case, they can create<http://schema.pinterest.com>
> > and put up their extensions, specifying how it links with
> > core<http://schema.org> . We will refer to these as external extensions.
> >
> > How it works for webmasters
> > All of Schema.org core and all of the reviewed extensions will be
> > available from the<http://schema.org> website. Each extension will be linked
> > to from each of the touch points it has with the core. So, if an extension
> > (say, having to do with Legal stuff)
> > creates<http://legal.schema.org/LegalPerson> which is a subclass
> > of<http://schema.org/Person> , the Person will link to LegalPerson.
> > Typically, a webpage / email will use only a single extension (e.g.,
> > legal), in which case, instead of ‘<http://schema.org> ’ they say
> > ‘<http://legal.schema.org> ’ and use all of the vocabulary
> > in<http://legal.schema.org> and<http://schema.org> .
> >
> > As appropriate, the main<http://schema.org> site will also link to
> > relevant external extensions. With external extensions, the use of multiple
> > namespaces is unavoidable.
> >
> > What does someone creating an extension need to do
> > We would like extension creators to not have to worry about running a
> > website for their extension. Once the extension is approved, they simply
> > upload a file with their extension into a certain directory on github.
> > Changes are made through the same mechanism.
> >
> > Since the source code for<http://schema.org> is publicly available, we
> > encourage creators of external extensions to use the same application.
> >
> > Examples
> >
> > Archives example in RDFa
> >
> > This example uses a type that makes sense for archival and bibliographic
> > applications but which is not currently in the<http://schema.org> core:
> > Microform, defined as "Any form, either film or paper, containing
> > microreproductions of documents for transmission, storage, reading, and
> > printing. (Microfilm, microfiche, microcards, etc.)"
> >
> > The extension type is taken from http://bibliograph.net/Microform
> > <http://bibliograph.net/Microform> , (which on this proposed model would
> > move to<http://bib.schema.org> ) which is a version of the
> > opensource<http://schema.org> codebases that overlays bibliographic extras
> > onto the core<http://schema.org> types. The example is adapted from
> > http://schema.org/workExample <http://schema.org/workExample> .
> >
> >
> > <div vocab="http://bib.schema.org/">
> > <p typeof="Book" resource="http://www.freebase.com/m/0h35m">
> > <em property="name">The Fellowship of the Rings</em> was written
> > by
> > <span property="author">J.R.R Tolkien</span> and was originally
> > published
> > in the <span property="publisher" typeof="Organization">
> > <span property="location">United Kingdom</span> by
> > <span property="name">George Allen & Unwin</span>
> > </span> in <time property="datePublished">1954</time>.
> > The book has been republished many times, including editions by
> > <span property="workExample" typeof="Book">
> > <span property="publisher" typeof="Organization">
> > <span property="name">HarperCollins</span>
> > </span> in <time property="datePublished">1974</time>
> > (ISBN: <span property="isbn">0007149212</span>)
> > </span> and by
> > <span property="workExample" typeof="Book Microform">
> > <span property="publisher" typeof="Organization">
> > <span property="name">Microfiche Press</span>
> > </span> in <time property="datePublished">2016</time>
> > (ISBN: <span property="isbn">12341234</span>).
> > </span>
> > </p>
> > </div>
> >
> > Alternative RDFa:
> >
> > The example above puts all data into the extension namespace. Although
> > this can be mapped back into normal<http://schema.org> it puts more work
> > onto consumers. Here is how it would look using multiple vocabularies:
> >
> > <div vocab="http://schema.org/ <http://schema.org/> " prefix="bib:
> > http://bib.schema.org/">
> > <p typeof="Book" resource="http://www.freebase.com/m/0h35m">
> > <em property="name">The Fellowship of the Rings</em> was written
> > by
> > <span property="author">J.R.R Tolkien</span> and was originally
> > published
> > in the <span property="publisher" typeof="Organization">
> > <span property="location">United Kingdom</span> by
> > <span property="name">George Allen & Unwin</span>
> > </span> in <time property="datePublished">1954</time>.
> > The book has been republished many times, including editions by
> > <span property="workExample" typeof="Book">
> > <span property="publisher" typeof="Organization">
> > <span property="name">HarperCollins</span>
> > </span> in <time property="datePublished">1974</time>
> > (ISBN: <span property="isbn">0007149212</span>)
> > </span> and by
> > <span property="workExample" typeof="Book bib:Microform">
> > <span property="publisher" typeof="Organization">
> > <span property="name">Microfiche Press</span>
> > </span> in <time property="datePublished">2016</time>
> > (ISBN: <span property="isbn">12341234</span>).
> > </span>
> > </p>
> > </div>
> >
> > Here is that last approach written in JSON-LD (it works today, but would
> > be even more concise if the<http://schema.org> JSON-LD context file was
> > updated to declare the 'bib' extension):
> >
> > <script type="application/ld+json">
> > {
> > "@context": [ "http://schema.org/",
> > { "bib": "http://bib.schema.org/" } ],
> > "@id": "http://www.freebase.com/m/0h35m",
> > "@type": "Book",
> > "name": "The Fellowship of the Rings",
> > "author": "J.R.R Tolkien",
> > "publisher": {
> > "@type": "Organization",
> > },
> > "location": "United Kingdom",
> > "name": "George Allen & Unwin",
> > },
> > "datePublished": "1954",
> > "workExample": {
> > "@type": "Book",
> > "name": "Harper Collins",
> > "datePublished": "1974",
> > "isbn": "0007149212"
> > },
> > "workExample": {
> > "@type": ["Book", "bib:Microform"],
> > "name": "Microfiche Press",
> > "datePublished": "2016",
> > "isbn": "12341234"
> > }
> > }
> > </script>
> >
> >
> > GS1 Example
> >
> > <script type="application/ld+json">
> > {
> > "@context": "http://schema.org/",
> > "@vocab": "http://gs1.schema.org/",
> > "@id": "http://id.manufacturer.com/gtin/05011476100885",
> > "gtin13": "5011476100885",
> > "@type": "TradeItem",
> > "tradeItemDescription": "Deliciously crunchy Os, packed with 4 whole
> > grains. Say Yes to Cheerios",
> > "healthClaimDescription": "8 Vitamins & Iron, Source of Calcium & High
> > in Fibre",
> > "hasAllergenRelatedInformation": {
> > "@type": "gs1:AllergenRelatedInformation",
> > "allergenStatement": "May contain nut traces"
> > },
> > "hasIngredients": {
> > "@type": "gs1:FoodAndBeverageIngredient",
> > "hasIngredientDetail": [
> > {
> > "@type": "Ingredient",
> > "ingredientseq": "1",
> > "ingredientname": "Cereal Grains",
> > "ingredientpercentage": "77.5"
> > },
> > {
> > "@type": "Ingredient",
> > "ingredientseq": "2",
> > "ingredientname": "Whole Grain OATS",
> > "ingredientpercentage": "38.0"
> > }
> > ]
> > },
> > "nutrientBasisQuantity": {
> > "@type": "Measurement",
> > "value": "100",
> > "unit": "GRM"
> > },
> > "energyPerNutrientBasis": [
> > {
> > "@type": "Measurement",
> > "value": "1615",
> > "unit": "KJO"
> > },
> > {
> > "@type": "Measurement",
> > "value": "382",
> > "unit": "E14"
> > }
> > ],
> > "proteinPerNutrientBasis": {
> > "@type": "Measurement",
> > "value": "8.6",
> > "unit": "GRM"
> > }
> > }
> >
> > </script>
> >
> > This example shows a possible encoding of the GS1 schemas overlaid
> > onto<http://schema.org> . It uses JSON-LD syntax, which would support
> > several variations on this approach. It is based on examples from GS1's
> > proposal circulated to the<http://schema.org> community recently.
> > (https://lists.w3.org/Archives/Public/public-vocabs/2015Jan/0069.html
> > <https://lists.w3.org/Archives/Public/public-vocabs/2015Jan/0069.html> ).
> > Instead of writing
> > "@context": "http://schema.org/", "@vocab": "http://gs1.schema.org/
> > <http://gs1.schema.org/> ", it would be possible to simply write "@context":
> > "http://gs1.schema.org/ <http://gs1.schema.org/> ".
> >
> >
> >
> >
> >
> >
> > >
Received on Friday, 20 March 2015 08:22:06 UTC