Re: [xml-dev] ID/IDREF is evil

Actually, this brings up something I've been thinking about for a while. It is typical to think of an XML document as being a self-contained entity, which makes sense from an XPath perspective, but once you start thinking about databases of XML documents, this does not always hold true. Indeed, in that context, even XLink is predicated upon using a URI that also bears function as a URL. (xlink:href="" Yet even this is local to the database in question. Once this document leaves the domain of that database, then the @xlink:href link becomes meaningless. This points to the need for a global identifier as a data-type, one likely based on xs:anyURI, that nonetheless has the specific semantics of a weak identifier (the assumption then being that there exists a target for an IDREF, but that target may not in fact be within the accessible context for that resource.�

Kurt Cagle
Invited Expert, XForms Working Group, W3C

Managing Editor, XMLToday.org

kurt.cagle@gmail.com

443-837-8725

On Wed, Feb 19, 2014 at 2:33 PM, Kurt Cagle <kurt.cagle@gmail.com> wrote:

On Tue, Feb 4, 2014 at 4:52 PM, Arjun Ray <arjun.ray@verizon.net> wrote:

| Because idref is only defined relative to its enclosing document,
| this means that it's remarkably difficult to create a reference
| to remote entities, meaning that any NIEM document effectively
| has to contain the entire serialization of all of its objects.

I'm not sure I follow this. �IDREF is far from a general purpose
reference mechanism. �It's for intra-document cross-referencing only.
(See the FPML specs for reasonable use.)

Too much water has flowed under too many bridges to bring up the
dreaded H-word again, so I'll let it go at that.

Arjun,

That was in fact the point that I'm trying to make. There was a decision made, early on in the evolution of NIEM, that s:id and s:ref constructors were defined as xs:ID and xs:IDREF respectively. I felt that this was a profound mistake, because it takes what is at heart a construct proxy for a real world object and assigns it what is, intrinsically, a local rather than global identifier.

Kurt Cagle
Invited Expert, XForms Working Group, W3C
Managing Editor, XMLToday.org
kurt.cagle@gmail.com

443-837-8725