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

Alan,

This came up before when I suggested that we add Onix as an OID. Onix
being an XML schema.

General consensus at the time was for solution 1 but this was definitely
a theorectical discussion rather than practice.

However, strictly speaking we should be doing the same for MARC (i.e.
request ISO2701 as the record syntax and MARC21 etc. via comspec!)

Matthew

> -----Original Message-----
> From: Alan Kent [mailto:ajk@mds.rmit.edu.au] 
> Sent: 13 March 2002 00:36
> To: ZIG
> Subject: Record syntaxes and schemas - XML, Dublin Core, etc
> 
> 
> 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, 14 March 2002 17:14:09 UTC