RE: XMI

[Arofan Gregory <arofan.gregory@commerceone.com>]

Folks:

In similar efforts here at Commerce One, we also found that for
automatically generating reusable component models (a very
structure-intensive activity), XMI was not sufficient. (This also is
obviously not what it was initially designed for). I agree with Martin's
assesment - we would need to add a level of hierarchy around the XMI
descriptions of objects to describe the exact set of objects as viewed for a
particular purpose (i.e, to describe their contextual reuse within a
business document in an XML schema or DTD). The information captured in the
model is critical, it's just that we need a different syntax.

Cheers,

Arofan

-----Original Message-----
From: Martin Bryan [mailto:mtbryan@sgml.u-net.com]
Sent: Friday, May 26, 2000 12:16 AM
To: ebxml-core@lists.oasis-open.org; Chris
Subject: Re: XMI


>Getting back to XMI, the XML in the XMI is really quite "flat" because a
>UML model has no hierarchy.  If you want a hierarchical DTD, then don't
> choose XMI, but if you want a DTD that can be used to transport
> faithfully the object instances from the application, then XMI is the
> tool

This is the main criticism of XMI. Without structured messages you cannot
have structured queries. Without structure you end up with having to adopt a
naming scheme that differentiates the different contexts within which a data
object occurs. When you name object based on their context they are no
longer reusable (see BSR for examples). Reusable core components need to be
context independent. They need to be placed in contexts within messages.
Therefore the messages need to be hierarchical. Therefore XMI is not
suitable for ebXML.

Martin Bryan