Re: [ubl] Proposed addition to 2.1 documented constraints - no schema location hints

["G. Ken Holman" <gkholman@CraneSoftwrights.com>]

At 2009-10-16 19:48 +0200, JAVEST by Roberto Cisternino wrote:
>I am not aware of the requirement to use RELAX-NG, however the W3C 
>XML Schema is a normative syntax for UBL.

No, it is the normative schema.  It is a set of constraints.  The 
choice of having done so has magically added support for these 
non-XML attributes for every document that uses it.

>Are we going to provide other normative syntaxes ?

No, I expect not.

But nor do we prohibit users from using any XML tools on UBL data 
either.  If someone wants to use RELAX-NG on their XML then they have 
to know that because we do not prohibit xsi:* for platform 
portability that they have to now accommodate that trading partners 
may be sending them documents with these rogue attributes.

My intent on suggesting this is to promote interoperability by 
recommending that UBL documents meant for interchange not include 
platform-specific attributes introduced by W3C Schema that are not 
part of the UBL vocabulary.

>G. Ken Holman ha scritto:
>>But I sincerely believe platform dependencies have no role in an 
>>interchange document and can only introduce problems for recipients.
>I agree it is not related to the interchange of data, but within 
>simple systems where a sophisticated xml catalog resolver is not 
>available the xsi schemaLocation could provide precious information 
>expecially for instances where the namespace URI do not provide full 
>information about the XML Schema version/customization/profile.

But your precious location information that you use in your UBL 
document on your system may generate errors on my system if (for the 
same reasons you cite) I'm obliged to use an XSD tool that respects 
the xsi:* values.  Without the prohibition then you send me your 
instance with your attribute value and I now have to edit the 
document I receive from you before I can work with it.

With the prohibition then I don't see any of your private location 
information that is meaningless to my system.

>Instead, a simple system could be resolving the XML Schema location 
>internally by just retrieving the schema name from the 
>xsi:schemaLocation.    In fact the schema name could be the original 
>name used for that kind of customization or profile.

That might be what it is on your system, but if my schemas are in 
different directories or on different disks, then it isn't going to work.

>So if the schema name is "UBL-Invoice-2.0-Watusi-Tall-1.0.xsd"  the 
>receiver could match this file locally on their system using just 
>the name and ignoring the original path of the sender.

How is the original path ignored?  If I have to go into the file and 
hack that attribute to make it work, then I'm not working with the 
instance as received.  And that isn't scalable if I'm getting 
thousands of documents.

>I know this seems to be stupid or crazy, but implementations are 
>very similar to my example around the world... :)

Fine, then, I'm not supposed to worry about this issue.  I see proper 
use of XML catalogues in tools like Oxygen, but many years ago when I 
first looked at XML Spy (I haven't looked at it in a long time), this 
attribute was crucial for the correct behaviour of the editor.

If a recipient has none of the problems I've anticipated when opening 
a file from a sender that has a pointer to the sender's internal 
system, then my worries are addressed.

Thanks, Roberto, for bringing this to my attention.  We have nothing, 
then, to put into the documentation.  Nevertheless, I'll still be 
including it in my training material as I personally can think of the 
situations I've described where the attribute gets in the way (and it 
isn't part of the UBL vocabulary).

. . . . . . . . . . Ken

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