RE: [ubl-dev] XML NDRs: UBL 2.0, 2.1, CEFACT 2.1, 3.0

["Crawford, Mark" <mark.crawford@sap.com>]

>I think the reason for the UBL design was to allow custom use of
>substitution groups (which require that elements be defined at a
>global level and referenced from types rather than defined locally
>in the types themselves). This combines with UBL's modular design
>to contribute to UBL's use of 1) imports and 2) multiple namespaces
>and their prefixes. 

Sorry, no it wasn't even in the discussions we had. Substitution groups were rejected out of hand by UBL in V1 and had no part in the Garden of Eden solution or the use of global elements.  The reason for imports centered around tying namespaces to vocabularies for management and versioning.

AS for UN/CEFACT, we have moved from a combination of import/include to packages with includes to better manage and use namespaces and in recognition of the impact imports - especially large imports such as a common reusable schema - has on performance since they must be loaded into memory in their entirety. This approach significantly lessens the need for flattening.

Kind Regards,
Mark