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Re: Requirements for profiles

From: Ruben Verborgh <Ruben.Verborgh@UGent.be>
Date: Mon, 20 Nov 2017 12:21:00 +0000
To: "kcoyle@kcoyle.net" <kcoyle@kcoyle.net>
CC: "public-dxwg-wg@w3.org" <public-dxwg-wg@w3.org>
Message-ID: <D7A5E9A0-82D3-4814-B391-AB036100221D@ugent.be>
Hi all,

> the charge is to define guidance for profiles "in
> general" not just DCAT, and that DCAT profiles would try to meet the
> terms of that guidance. This is why I am a bit confused about Ruben's
> distinction and would like to understand the differences that he perceives.

I would define them as follows.

A media type (or content type) defines a set of syntactic constraints, structural constraints,
and/or semantic interpretations that can apply to a given document.

A profile defines a set of additional structural and constraints and/or semantic interpretations
that can apply to a given document on top of that document's media type.

A DCAT profile is a profile with structural constraints for datasets.

(This last definition can be improved; I'm mostly concerned with the first two.)

> Now, within a certain community,
> composition may be possible because you've all agreed on the details of
> your profiles. But I don't think it is possible against an arbitrary set
> of profiles.

Indeed, and that's not a problem.

I emphasize that generic profiles can be seen as really simple things.
Examples of profiles could be:
 has a "title" element with a string as value
 has a "links" element with an array as value

So then, trivially, the following JSON document conforms to both profiles:

{
  "title": "My Title",
  "links": ["http://example.org/"]
}

That's how easy things can be.

> What I would like to avoid is having to code profiles based
> on their level or type of description of the vocabulary.

There's no need to do that.

Note that, even in the trivial example above,
I'm not mandating that a machine-readable description language exists
to write those constraints.
That's not something we want to solve in general.

> I would like to see a real life use case for composition before we take
> this further, not a theoretical one.

Even though I'm the one who brought up the word "composition",
let's maybe forget about it for now.
All I was trying to say is that representations can conform to multiple profiles,
especially if those profiles are lightweight things as in my example above.

>> "composition" is ill defined in this context.

Indeed, on purpose.

>> All DCAT needs to do is to allow a dataset to declare conformance with multiple profiles.

+1

Best,

Ruben
Received on Monday, 20 November 2017 12:21:30 UTC

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