Re: Record syntaxes and schemas - XML, Dublin Core, etc

I have a proposal to deal with this issue. See:
http://www.loc.gov/z3950/agency/zig/meetings/oclc2002/compspec2.html
It's for discussion at the April meeting.
--Ray

Alan Kent wrote:
> 
> A question came up in my mind on a different list, but its a Z39.50 issue
> so I will ask it here. Its probably a theory versus practice question.
> I think I know the correct theoretical approach as defined by Z39.50,
> but in practice I don't know if anyone uses it, currently supports it,
> or is likely to support it - so does that make it the wrong way to go?
> Its an old issue by the way.
> 
> Problem: I have a database of XML documents. I want to be able to ask
> for records to come back as the full document (marked up in XML) or as
> dublin core metadata (again, marked up as XML).
> 
> There are 3 solutions that come to mind. Comments appreciated (yes,
> no, screams of anguish, that sort of thing).
> 
> Solution 1:
> I think the theoretically correct approach is In present requests, use
> recordComposition of 'complex', then in the 'Specification' type specify
> the optional schema OID along with the element set names. The schema OID
> would be different for the two forms of XML, but the record syntax OID
> for both would be the XML record syntax.
> 
> The only problem I have with this is that it requires version 3 of
> the protocol, and who actually supports it? How many clients support
> it? I can see that preferred record syntax OIDs and element set names
> can be programmed, but not schema OIDs. This may be because many clients
> are still V2 for example.
> 
> Solution 2:
> Allocate a new record syntax OID for Dublin Core in XML. This might
> be done by adding a new digit on the end of the XML OID. That is,
> all OIDs starting with the XML OID must be XML. 1.2.840.10003.5.109.10
> is for generic XML, and 1.2.840.10003.5.109.10.1 is for Dublin Core etc.
> The advantage is most clients can be configured to choose a record syntax
> OID.
> 
> Solution 3:
> Use the XML record syntax OID, but rely on usage of element set names.
> That is, introduce standard element set names for 'DC-B', 'DC-F' etc.
> 
> I am interested in both theory and practice. It has come up for me
> personally with respect to ZiNG/SRW and translating SRW arguments
> into Z39.50 requests. Its particularly a problem for my implementation,
> as while our server has implement lots of Z39.50 (explain, extended
> services, v3, concurrent operations, resource reports, multiple record
> syntaxes etc), the one area we have not done anything to date is schemas.
> And if no clients (or even most), then I have a quandry of doing
> "the right thing" (which could be a lot of work) or "something that
> is practical and is interoperable".
> 
> Feedback appreciated.
> 
> Alan
> --
> Alan Kent (mailto:ajk@mds.rmit.edu.au, http://www.mds.rmit.edu.au)
> Postal: Multimedia Database Systems, RMIT, GPO Box 2476V, Melbourne 3001.
> Where: RMIT MDS, Bld 91, Level 3, 110 Victoria St, Carlton 3053, VIC Australia.
> Phone: +61 3 9925 4114  Reception: +61 3 9925 4099  Fax: +61 3 9925 4098

Received on Thursday, 21 March 2002 17:33:01 UTC