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The Data Portal use cases (was: Shapes vs Classes (in LDOM))

From: Holger Knublauch <holger@topquadrant.com>
Date: Sun, 25 Jan 2015 20:22:20 +1000
Message-ID: <54C4C3DC.6020800@topquadrant.com>
To: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
Hi Jose,

On 1/24/15, 5:33 PM, Jose Emilio Labra Gayo wrote:
>
>     It would help to have specific instances and class definitions, to
>     make sure we talk about the same problems. Can you provide some?
>
>
> The real life example I had in mind was the user case the I proposed 
> yesterday which is documented in [1]. The documentation of the two 
> linked data portals using ShEx was provided here in [2] and [3].

I have read through those references. Thanks for the links.

>
> In that case, I did the data model and I added rdf types, but I there 
> may be plenty of situations and other models where one would not need 
> to add those rdf:type declarations and it would not mean that they are 
> not right.

This did not strengthen the case for separating classes and shapes yet. 
Your example uses classes too, and looking at your shapes, they all 
start by checking for the presence of an rdf:type triple. So the shapes 
basically just mirror the classes.

Can you provide an example that illustrates your point better?

>
> Notice that although the shapes of qb:Observation's in both portals 
> look quite similar (the data model is in fact very similar and was 
> made by the same person), in practice it should not necessarily be the 
> case. For example, the property used to associate time to observations 
> varied from one portal to the other.

This again sounds rather abstract and hypothetical. Can you provide 
specific definitions and/or sample data? A relevant slide seems to be 
slide 19 on http://www.slideshare.net/jelabra/linked-dataquality-2014 
which shows two uses of the Observation class. One is using a property 
ces:ref-year, the other is using lb:time. Why would it be a problem to 
attach both into the same class Observation? To keep them separate, you 
could save their ldom:property declarations in different files/graphs 
for each portal. Those files would import the base schema. Do you have 
examples for conflicting definitions that would cause issues if those 
graphs were merged? Also, why can't you just create two subclasses of 
Observation, for each of the two portals?

Thanks
Holger

>
>
> [1] [1] Validating and Describing Linked Data Portals using RDF Shape 
> Expressions, Jose Emilio Labra Gayo, Eric Prud'hommeaux, Harold Solbrig,
> 1st Workshop on Linked Data Quality, Sept. 2014, Leipzig, Germany
> PDF: http://labra.github.io/ShExcala/papers/ldq2014.pdf
> Slides: http://www.slideshare.net/jelabra/linked-dataquality-2014
>
> [2] http://weso.github.io/wiDoc/
> [3] http://weso.github.io/landportalDoc/data/
>
Received on Sunday, 25 January 2015 10:22:53 UTC

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