> But yes, something I was turning over after reading Andy's initial
> message on this thread (and which I think is also touched on in John
> Casey's comment about a repository requiring the "full monty" and Scott
> Wilson's comment on "prior agreement" about data exchanged between
> services) is whether there is a potential tension here between the
> requirements/preferences of a (in OAI-PMH terms) "data provider" (the
> agent who provides/exposes metadata) - "you can't really expect me to
> provide *all* this stuff!" - and those of a "service provider" that uses
> that metadata as the basis of a new service - "I'd really quite like to
> rely on having present all those elements that UK LOM Core says is
> mandatory".
>
> I don't have an answer for how to resolve that tension! ;-)
In Z39.50 world, this is what the "Explain" request is for - in Web Services
this is the function of WSDL. Basically, metadata (of the computing rather
than library variety) is needed for describing what a service consumer may
reasonably expect the service provider to provide.
Of course, if there is a single profile for all providers it makes life
easier...but at least being able to interrogate a service for its agreements
lets you make a decision whether to use the provider, or whether changes to
consumer code are needed to support connecting to it.
There may also need to be provision in exchanges for specifying requirements
and dealing with exceptions at the request level - e.g. a request by a
consumer to "give me a record with x,y, and z in it" should return an
exception code rather than try to provide a record that only contains "y".
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