Re: XMI

["Martin Bryan" <mtbryan@sgml.u-net.com>]

>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