I would put this comment round a different way:
The schema provides XML element definitions for dc elements, without
providing an explicit or implicit context for their use. What usage in XML
documents is this intended to support? Is this schema intended for reuse
within local metadata standards? - if so, then our experience suggests that
providing XML Schema Type rather than Element definitions is more helpful,
since local standards are likely to restrict values permitted for elements.
We have drafted a metadata standard for XML schemas within the UK Government
GovTalk collection - this is based on the UK e-Government Metadata Standard,
which is itself based on Dublin Core. Having two levels of inheritance of
metadata element definitions involved (with specialization at each level)
brought out some interesting design issues in the XML representation - not
least, that the XML representation had to be a fairly uncomfortable
compromise between the semantics (intended meaning) of the metadata, and
what could be said easily in an XML schema to validate the metadata.
The document is expected to go out for public consultation soon on the UK
GovTalk website (http://www.govtalk.gov.uk) - consultation responses from
the dc community would be v. welcome.
Ann W.
Ann M Wrightson MA MBCS
Prif Ymgynghorydd / Principal Consultant
alphaXML Cyf/Ltd
http://www.alphaxml.com
Gwasaneuthau XML: e-Lywodraeth, e-Fasnach, e-Gyhoeddi
XML services to Government and Industry
-----Original Message-----
From: The broadest of mailing lists related to the international Dublin
Core effo [mailto:[log in to unmask]]On Behalf Of Renato Iannella
Sent: 24 April 2002 13:27
To: [log in to unmask]
Subject: Re: OAI and DCMI announce DC-Simple Schema Declaration
--On 24/04/2002 6:51 -0400 Weibel,Stu wrote:
> DCMI and OAI are pleased to announce an XML schema for unqualified DC
> metadata that facilitates the declaration of modular metadata components.
There is a small but significant error in this XML Schema.
No "root" element has been defined, and as the 15 DC elements
can only accept string values, you can only have one element
in your DC metadata instance.
(This has been verified using XML Spy V4.3.)
A new root/parent element, such as <dc-record> should be added.
For example:
<xs:element name="dc-record">
<xs:complexType>
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element ref="title"/>
<xs:element ref="creator"/>
...
<xs:element ref="coverage"/>
<xs:element ref="rights"/>
</xs:choice>
</xs:complexType>
</xs:element>
Also, there is a Group defined in the XML Schema (elementsGroup)
but is not used anywhere.
I noticed the use of the xml:lang attribute for all elements.
Did you consider adding an "encoding" attribute to support
the specification of encoding schemes (eg URI, W3CDTF, RFC1766)?
DCMES V1.1 mentions a few of these as "recommended best practice".
If so, you can simply add:
<xs:attribute name="encoding" type="xs:string" "use="optional"/>
to the "elementType" complex type.
Cheers...Renato <http://purl.net/renato>
Chief Scientist, IPR Systems Pty Ltd <http://iprsystems.com>
Open Digital Rights Language (ODRL) <http://odrl.net>
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