[ver] (AW/Fwd) to consider before call

["Stephen Green" <stephen_green@seventhproject.co.uk>]

 

----- Original Message -----

From: A. G.

To: Stephen Green

Sent: Tuesday, April 12, 2005 1:47 PM

Subject: Re: [ver] Anything to consider before call?

Stephen:

 

Many thanks.

 

Yes, I think I actually figured out a solution, although i haven't had time to really work up the samples yet.

 

Substitution groups.

 

I was looking at your samples, and I realized that the one thing we do differently in the SDMX implementation of this aspect of NDR (we don't use all the rules, as they don't always apply) is that we have each extendable type represented as the head of a substitution group.

 

Thus:

 

In NS A v. 1.0, I declare Item and Line. Each type is the head of a substitution group.

 

In NS B v 1.0, I declare the Invoice, as per your example from our earlier call.

 

If I go to create v. 1.1 of these namespaces, I can extend the Item in NS A v. 1.1, and also extend the Line (which contains the Item). If I indicate that the Item is a member of the Item substitution group, however, then I get the extended version of Item instead of the old one when I create the new Line (which, of course, I use in the new Invoice, which can also be extended).

 

Had you considered this approach? It has some ramifications, but avoiding the problem you ran into is exactly why substitution groups were invented. I know this was discussed in NDR soime time ago, but it clearly didn't make it into the spec.

 

I thionk we should discuss this on the call, unless jet-lag is making me miss some obvious flaw.

 

Cheers,

 

Arofan

Stephen Green <stephen_green@seventhproject.co.uk> wrote:

Arofan

 

I just realised you can't post to the ubl list.

If you've anything you'd like be posted to the list

before the meeting today, feel free to post it

to me and I'll forward it on. However I'll be away

from email for 1 hour prior to the call.

 

Unfortunately I'll be out of email range Thurs

and Friday but we can sort something out before

then. (The modeling team have had to send me

to a meeting in Europe so I'll only have limited

contact Thursday and Friday I'm afraid.)

 

All the best

 

Steve