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Re: PROV-ISSUE-493: prov:type has type Value; valid values too general, include number, datetime, boolean, etc. [prov-dm]

From: Luc Moreau <l.moreau@ecs.soton.ac.uk>
Date: Wed, 12 Sep 2012 14:22:42 +0100
Message-ID: <EMEW3|f89a4e1f4f7be768c9ba68ef4e58180do8BEMi08l.moreau|ecs.soton.ac.uk|50508CA2.6040004@ecs.soton.ac.uk>
To: public-prov-wg@w3.org
Hi Curt and Stephan,

I am less certain about this change.

First, do you mean QName as in xsd:QName?
Why not use the prov:QualifiedName, which we already have (and can be 
transformed into uris).

But then, why just prov:QualifiedName , and why not URI (xsd:anyURI)?

The reason why this was left unspecified is that PROV, intentionally, 
refrained from defining
what a type system is, and therefore, a consequence, was that we didn't 
define how to
represent a given type value.


On 09/12/2012 01:27 PM, Curt Tilmes wrote:
> I agree with Stephan.  The real reason for having prov:type at all is
> to encourage consistency.  Qnames encourage capturing semantic meaning
> beyond free text.
> The types we've defined
>   http://www.w3.org/TR/prov-dm/#term-attribute-type
> set a precedent for the type of types we think should fill prov:type,
> and the discussion of prov:type in the extensibility points section:
>   http://www.w3.org/TR/prov-dm/#extensibility-section
> shows examples defining new prov:types as qnames in other namespaces.
> This would require some rework of examples, but I think the change
> would be valuable in the long term.
> Curt
> On 09/12/2012 02:19 AM, Stephan Zednik wrote:
>> A quick reminder about this issue.
>> Looking at the PROV-DM document again I see a few examples where simple
>> non-qname strings are used for prov:type values.
>>  From example 21 (http://www.w3.org/TR/prov-dm/#anexample-communication)
>> prov:type="fine paying, check writing, and mailing"
>> I think in most if not all of these cases the prov:type value could be
>> simplified to a qname.
>> I understand this change is significant due to the timing of the
>> suggestion, but I believe the benefit of making this change is 
>> worthwhile.
>> Thanks,
>> --Stephan
>> On Sep 4, 2012, at 11:18 AM, Provenance Working Group Issue Tracker
>> <sysbot+tracker@w3.org <mailto:sysbot+tracker@w3.org>> wrote:
>>> PROV-ISSUE-493: prov:type has type Value; valid values too general,
>>> include number, datetime, boolean, etc. [prov-dm]
>>> http://www.w3.org/2011/prov/track/issues/493
>>> Raised by: Stephan Zednik
>>> On product: prov-dm
>>> The value of prov:type is a Value
>>> (http://www.w3.org/TR/prov-dm/#term-value) which has the following
>>> definition:
>>> A value ◊ is a constant such as a string, number, time, qualified
>>> name, IRI, and encoded binary data, whose interpretation is outside
>>> the scope of PROV. Values can occur in attribute-value pairs.
>>> Each kind of such values is called a datatype. Use of the following
>>> data types is recommended.
>>> The RDF-compatible [RDF-CONCEPTS] types, including those taken from
>>> the set of XML Schema Datatypes [XMLSCHEMA11-2];
>>> Qualified names introduced in this specification.
>>> The normative definitions of these datatypes are provided by their
>>> respective specifications.
>>> This means that numbers, datetimes, booleans, and unstructured strings
>>> are valid values of prov:type.  The prov value section on RDF
>>> compliance also seems to suggest there should be a prov:type datatype
>>> property in prov-o, which to my knowledge does not currently exist.
>>> So my question is, are we ok with numbers, datetimes, booleans as
>>> valid values of prov:type?  All of the examples in the DM document
>>> appear to use qnames for values of prov:type.
>>> Second, is there support for a proposal to restrict values of
>>> prov:type to qnames?

Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Wednesday, 12 September 2012 13:23:13 UTC

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