[sc34wg3] Association items

[Murray Altheim]

Lars Marius Garshol wrote:
> * Murray Altheim
> |
> | I realize that Lars Marius has argued that association type (along
> | with other things) should not be optional in XTM, whereas I would
> | suggest that XTM be left alone and push this kind of thing into a
> | proper constraint language operating at a higher schema level -- the
> | XTM DTD is really only meant to express syntax-level constraints.
> 
> What we agreed in Amsterdam (this year) was to leave XTM alone, but to
> require an association type in TMDM. However, TMDM will define a PSI
> for untyped associations that is inserted when no explicit type is
> given. Thus we avoid the ugliness of association.[type] sometimes
> being null, yet we keep backwards compatibility.
> 
> The implication is that we consider all untyped associations to have
> the same type, but this seems fair.

When that PSI becomes available, could you forward an announcement
to the group? I'm currently using a similar PSI within Ceryle and
would like to either add it as an equivalent subject or substitute
it (depending on where I am in my "product lifecycle" when the PSI
becomes available). Thanks!

> Anyone wanting to disallow such associations should be able to do so
> by means of TMCL.

Yes, this seems like the correct place for such a constraint.

Murray

......................................................................
Murray Altheim                          http://www.altheim.com/murray/
Strategic and Services Development
The Open University Library
The Open University, Milton Keynes, Bucks, MK7 6AA, UK               .

       The moment you come to trust chaos, you see God clearly.
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