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Re: [dxwg] refining the definition of profile in response to the poll (#989)

From: Karen Coyle via GitHub <sysbot+gh@w3.org>
Date: Mon, 15 Jul 2019 16:00:35 +0000
To: public-dxwg-wg@w3.org
Message-ID: <issue_comment.created-511462861-1563206434-sysbot+gh@w3.org>
It seems to me that we have two "levels" of definition. 

1. To define what a profile is
2. To define what is the relationship of instance data to the profile.

I think that Tom's definition covers 1. I also think that a profile doesn't itself do or implement anything. There needs to be some intermediary between the data definitions in the profile and the instance data that one hopes will conform to the profile. That requires a process of validation. The profile itself is not a process - I see it as a declaration. In the XML world, an XML schema defines the data (and one could create a profile in XSD), but until you run  a validator (e.g. Schematron) you do not know whether the data conforms. With RDF one needs to run validation based on a SHACL or ShEx document. 

My conclusion is that the profile _defines_ but does not validate. Validation is a separate step, and therefore determination of conformance is not within the profile but its rules are defined by the profile. I find the wording in the [XML documentation](https://www.w3.org/TR/2008/REC-xml-20081126/) to be similar: "XML provides a mechanism to impose constraints on the storage layout and logical structure." XML does not constrain but provides the mechanism with which one can impose constraints. Then the document talks about "... describing the actions of an XML processor." So there is a processor that implements XML, the XML document is not that process.

I see the same difference between profiles and data validation against the profile. The latter is a process and I think that process is outside of our scope. In the DCMI profiles work, we are looking to align profiles with ShEx and perhaps SHACL so that those _processors_ can validate conformance. But we accept that profiles are documents that  _inform_ validation of instance data but are not themselves a validation process. If you have a profile and some instance data, you still need something else to determine conformance. It's not the profile itself.

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Received on Monday, 15 July 2019 16:00:38 UTC

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