Re: [whatwg] Proposal: allow itemid to record multiple identifiers for an item
On Wed, 5 Dec 2012, Ed Summers wrote: > > Was the "id" itemprop you used in your examples a hypothetical property > that would need to be defined at schema.org or elsewhere, or did you > find it defined already? Hypothetical. In the schema.org vocabulary, the existing "url" property could be used, maybe? Or a new one, of course. I couldn't quite tell from the schema.org documentation if "url" was intended to do this. -- Ian Hickson U+1047E)\._.,--,'``.fL http://ln.hixie.ch/ U+263A/, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
Re: [whatwg] Proposal: allow itemid to record multiple identifiers for an item
Ian, Thanks very much for the guidance re: using and . I like both solutions quite a bit better than leaning more on itemid for this use case. Was the "id" itemprop you used in your examples a hypothetical property that would need to be defined at schema.org or elsewhere, or did you find it defined already? //Ed
Re: [whatwg] Proposal: allow itemid to record multiple identifiers for an item
On Tue, 4 Dec 2012, Ed Summers wrote: > > Over on a schema.org related list [1] there has been a discussion about > making identifiers for bibliographic items (books, articles, etc) > available in microdata using itemid. The use case is well described in > the dev edition, with this example [2]: > > itemtype="http://vocab.example.net/book"; > itemid="urn:isbn:0-330-34032-8"> > Title > The Reality Dysfunction > Author > Peter F. Hamilton > Publication date > 26 January 1996 > > > Our use case is when a publisher wants to record multiple identifiers > for an item. For example The Reality Dysfunction also has an OCLC number > 225870439, which can be expressed as a URI, info:oclcnum/225870439. When a property isn't the sole unique identifier for an item, just use a property instead of itemid="", as in: http://vocab.example.net/book";> Title The Reality Dysfunction Author Peter F. Hamilton Publication date 26 January 1996 ...or, if continuing to use URLs makes more sense: http://vocab.example.net/book";> Title The Reality Dysfunction Author Peter F. Hamilton Publication date 26 January 1996 > One alternative to using itemid would be to define an oclcnum itemprop > to the relevant schema.org types. This solution is a bit unwieldy > because there are so many identifier types in the bibliographic world. I > imagine the same is similar in other domains. That's another possibility, yes. If having a large numbmer of properties is not practical for some reason, then having one property use a common syntax that can express all the identifier types (e.g. URLs, or the "type number" syntax in the first example above) can work too. > Another solution would be to come up with some generic identifier > mechanism, but I feel like this would then duplicate what itemid is > already doing. That's fine. itemid="" is intended just for the very specific case of there being a specific unique identifier that is globally used as the key by which a particular vocabulary's items are identified; if there's no such key, or there are many keys and none are more important than the others, then it's better to just use a property. Honestly, itemid="" isn't really intended to be a particularly widely used feature. This is reflected by the way the spec only has one example that uses itemid="", and that example's purpose is to demonstrate itemid="". It's really just a shorthand for a property (though not one whose name can be specified in itemprop=""), and if it doesn't quite fit, it's fine to ignore it and use something else. HTH, -- Ian Hickson U+1047E)\._.,--,'``.fL http://ln.hixie.ch/ U+263A/, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
[whatwg] Proposal: allow itemid to record multiple identifiers for an item
Hi WHATWG, Over on a schema.org related list [1] there has been a discussion about making identifiers for bibliographic items (books, articles, etc) available in microdata using itemid. The use case is well described in the dev edition, with this example [2]: http://vocab.example.net/book"; itemid="urn:isbn:0-330-34032-8"> Title The Reality Dysfunction Author Peter F. Hamilton Publication date 26 January 1996 Our use case is when a publisher wants to record multiple identifiers for an item. For example The Reality Dysfunction also has an OCLC number 225870439, which can be expressed as a URI, info:oclcnum/225870439. It would be convenient if we could say: http://vocab.example.net/book"; itemid="urn:isbn:0-330-34032-8 info:oclcnum/225870439"> Title The Reality Dysfunction Author Peter F. Hamilton Publication date 26 January 1996 But it appears that the current specification does not allow for this [3] """ The itemid attribute, if specified, must have a value that is a valid URL potentially surrounded by spaces. """ One alternative to using itemid would be to define an oclcnum itemprop to the relevant schema.org types. This solution is a bit unwieldy because there are so many identifier types in the bibliographic world. I imagine the same is similar in other domains. Another solution would be to come up with some generic identifier mechanism, but I feel like this would then duplicate what itemid is already doing. So, is it feasible for the Microdata specification to allow for multiple space separated identifiers in an itemid, similar to the set of space-separated tokens microsyntax [4]? Or is there an alternate solution that I'm missing? Thanks for your attention, //Ed [1] http://lists.w3.org/Archives/Public/public-schemabibex/2012Dec/.html [2] http://developers.whatwg.org/links.html#global-identifiers-for-items [3] http://www.whatwg.org/specs/web-apps/current-work/multipage/microdata.html#items [4] http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#set-of-space-separated-tokens
