Scott said:
> 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.
I think parts of this functionality could be provided (in the future!)
by the IE Service Registry (which provides a single point of access to
information about services (a la Explain/WSDL)) and/or the IE Metadata
Schema Registry (ditto for information about the metadata schemas used
in the metadata exposed).
However, that does depend on each data provider specifying and
disclosing to those shared services exactly what they are
providing/exposing. Going back to Andy's example that would seem to
imply that his three providers of descriptive metadata, e-learning
metadata and annotations would each state that they are providing
metadata conforming to a _different_ profile of LOM. Urk, I'm really not
sure that's the way to go.
Or alternatively they all say they are providing metadata conforming to
a single (very permissive) profile of LOM, and the service provider
doesn't know what subset they are actually going to get until they
receive the metadata records themselves.
> 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".
Cheers
Pete
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