W3C home > Mailing lists > Public > public-webid@w3.org > February 2013

Re: Problem with Hash based Linked Data URIs

From: Mo McRoberts <Mo.McRoberts@bbc.co.uk>
Date: Sat, 16 Feb 2013 15:04:18 +0000
To: Adrian Gschwend <ktk@netlabs.org>
CC: "<public-webid@w3.org>" <public-webid@w3.org>
Message-ID: <173F46AC-5144-4915-A152-9B877E8C5C21@bbc.co.uk>
As should be blindingly obvious to anybody who's worked with them, hash-based URIs are principally useful where a document describes a _single_ entity within its sphere of reference (though the nature of triples and many ontologies is that there may well be parts of descriptions of other things).

Ontologies/vocabs are a one solid case where it's really not a good idea to use them because it's hard to split them up into separately-served resources later.

(Ironically, as a redirecting service, if the PURL for GR had been http://purl.org/goodrelations/v1/ instead of http://purl.org/goodrelations/v1#, it could have redirected to either a hash-based or a hash-less URI  there's no benefit to hash-based URIs if you're always inserting a redirect _anyway_).

On the other hand in the case of "this is the document which describes me" or "this is the document which describes this book", it makes a lot of sense to use hash-based URIs because that document has a notion of a primary topic while anything else described is a supporting adjunct. Even if it's aggregated into a dataset, the subject used in that dataset would be a URI which resolves to that one-thing document URI.

M.

On Sat 2013-Feb-16, at 14:33, Adrian Gschwend <ktk@netlabs.org>
 wrote:

> On 16.02.13 12:10, Melvin Carvalho wrote:
>
>> Hi Kingsley, just trying to understand the problem better.  When I
>> click, http://purl.org/goodrelations/v1#BusinessEntity it takes me to
>> the section of the GR vocab that is related to BusinessEntity (via html
>> anchors).  What should it be doing?
>
> That's only because you requested it from a web browser, if you get that
> as RDF (via rapper for example) it will make a request to
> http://purl.org/goodrelations/v1 and instead of giving you the answer to
> what you really want to know  (#BusinessEntity) it downloads the whole
> ontology which according to rapper is 1834 triples. Everything after the
> # is handled client side and does not even get through the webserver.
>
> This is not handy at all when you start to write code, you get way more
> than you wanted to know and it gets harder to implement local caching
> for example. Did that done that, really no fun to implement properly
> with hash based URIs.
>
> So I'm really no fan of hash based URIs either, especially on bigger
> ontologies/datasets.
>
> cu
>
> Adrian
>
>
>
>
>
> --
> Adrian Gschwend
> @ netlabs.org
>
> ktk [a t] netlabs.org
> -------
> Open Source Project
> http://www.netlabs.org
>

--
Mo McRoberts - Technical Lead - The Space
0141 422 6036 (Internal: 01-26036) - PGP key CEBCF03E,
Zone 1.08, BBC Scotland, Pacific Quay, Glasgow, G51 1DA
Project Office: Room 7083, BBC Television Centre, London W12 7RJ



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Received on Saturday, 16 February 2013 15:04:55 UTC

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