- From: Jason Douglas <jasondouglas@google.com>
- Date: Thu, 17 Apr 2014 18:25:20 +0000
- To: Jarno van Driel <jarno@quantumspork.nl>
- Cc: Public Vocabs <public-vocabs@w3.org>
- Message-ID: <CAEiKvUBvBACZr5gwDPNvCpTVMbWdNYmGU0Ha1phpQa9Xta09Ww@mail.gmail.com>
Yup, that's messed up. Let's fix it! On Thu Apr 17 2014 at 11:15:43 AM, Jarno van Driel <jarno@quantumspork.nl> wrote: > "...if a relation is declared without an explicit subject, then the > subject will be assumed to be the current WebPage." > Got it. > > "It is legal for there to be multiple top-level entities." + "Current > clients make up their own heuristics for this..." > Brainfreeze! > How am I, as a developer, to deal with this? Does this mean I have to > somehow figure out which heuristics every parser/search engine uses, to be > able to have control or do I need to try to chain everything together such > that only one top-level entity is left? > > And how would I do this for a category page on for example an eCommerce > site. Which shows a range of Product entities on a CollectionPage, which > together form the main-content and where the CollectionPage, for lack of a > better term, only functions as a 'wrapper' for the list of products. > > "we probably do need a mechanism for indicating the "primary entity" of a > webpage when there is one..." > One the reasons why I asked my questions is because I encounter quite a > lot of markup on websites where people use @mainContentPage on entities > like Product. Now @mainContentOfPage has the expected type WebPageElement, > but many aren't aware of this. And since there is no property to indicate > which entity is the primary one I actually can completely understand they > try to resolve it like this. And frankly, I'm confused as well. > > > > On Thu, Apr 17, 2014 at 7:51 PM, Jason Douglas <jasondouglas@google.com>wrote: > >> It is legal for there to be multiple top-level entities. That >> description of WebPage is not meant to imply anything about the >> relationship of those top-level objects... all that is saying is that if a >> relation is declared without an explicit subject, then the subject will be >> assumed to be the current WebPage. >> >> That said, we probably do need a mechanism for indicating the "primary >> entity" of a webpage when there is one. Current clients make up their own >> heuristics for this, but I think it would be better to have an explicit way >> of stating that. >> >> -jason >> >> >> On Thu Apr 17 2014 at 10:41:47 AM, Jarno van Driel <jarno@quantumspork.nl> >> wrote: >> >>> I'm trying to understand semantic mechanisms better but am a bit >>> confused about schema.org/WebPage and I'd like to know how it works. >>> >>> Now it could well be I understand certain terminologies wrong, so please >>> bare with me and be so nice to correct me when needed. >>> >>> 1] The description of http://schema.org/WebPage says: >>> "Every web page is implicitly assumed to be declared to be of type >>> WebPage, so the various properties about that webpage, such as breadcrumb >>> may be used. We recommend explicit declaration if these properties are >>> specified, but if they are found outside of an itemscope, they will be >>> assumed to be about the page." >>> >>> code example: >>> <body itemscope itemtype="http://schema.org/WebPage"> >>> <!-- Content --> >>> </body> >>> >>> Now if the WebPage is the only entity is it then considered to be the >>> 'Subject', the 'Object' or both? >>> >>> 2] If the WebPage contains an entity, let's say a Product, without >>> specifying a property on the Product and I check this with Google's SDTT, I >>> see 2 'root' entities, since there is no property to chain the two >>> together. Yet I get the impression the Product gets treated as the >>> 'Object', since it's the Product that gets used for Rich snippet >>> extraction, and that therefore the WebPage is the 'Subject' : >>> >>> code example: >>> <body itemscope itemtype="http://schema.org/WebPage"> >>> <span itemprop="name">Page title</span> >>> >>> <div itemscope itemtype="http://schema.org/Product"> >>> <span itemprop="name">Product name</span> >>> <!-- Product properties --> >>> </div> >>> </body> >>> >>> Now since "Every web page is implicitly assumed to be declared to be of >>> type WebPage" I was wondering if there also is a property that is >>> 'implicitly assumed to be declared' (something like @contains) on the first >>> entity that comes after it, like Product in this case, which indicates that >>> the Product is the 'Object'? >>> >>> And if not, than how does a parser 'know' which of the entities is the >>> 'Subject' and which is the 'Object', shouldn't there be a predicate for >>> this? >>> >>> 3] When a WebPage contains a bunch of 'root' entities, how does a parser >>> make sense of this, does the DOM have anything to do with this? >>> >>> <body itemscope itemtype="http://schema.org/WebPage"> >>> <span itemprop="name">Page title</span> >>> >>> <div itemscope itemtype="http://schema.org/Product"> >>> <span itemprop="name">Product 1 name</span> >>> <!-- Product properties --> >>> </div> >>> >>> <div itemscope itemtype="http://schema.org/Product"> >>> <span itemprop="name">Product 2 name</span> >>> <!-- Product properties --> >>> </div> >>> >>> <div itemscope itemtype="http://schema.org/LocalBusiness"> >>> <span itemprop="name">Business name</span> >>> <!-- Product properties --> >>> </div> >>> </body> >>> >>> Now the above could be full of misunderstandings because I lack in >>> theoretical knowledge still, but that's exactly the thing I'm hoping to >>> change. Who can enlighten me? >>> >>> >>> >>> >>> >>> >
Received on Thursday, 17 April 2014 18:25:50 UTC