G'day,
I've been looking over the "Guidelines for implementing Dublin Core in
XML". It's a good and clear document however I have some queries and
comments about some things in it.
1. Rec 2: should use XML Namespaces to uniquely identify DC properties
Since these are guidelines, different implementations may choose to
define their XML constructs differently for the same DC property.
This will cause problems for tools expecting that an XML Namespace
corresponds to exactly one XML Schema definition.
For example, one implementation may use:
<metadata1 xmlns:dc="http://purl.org/dc/elements/1.1/">
...
<dc:identifier>http://example.org/foobar</dc:identifier>
...
and they have defined in an XML Schema that dc:identifier
is a URI.
Someone else uses this implementation
<metadata2 xmlns:dc="http://purl.org/dc/elements/1.1/">
...
<dc:identifier>335-300-323-3</dc:identifier>
...
and they have defined in an XML Schema that dc:identifier
is a xsd:string with some pattern facet.
Both would satisfy the guidelines, but will cause problems for an
integration tool that deals with both formats, since it will see two
different XML Schema definitions for the same element.
This problem seems to stem from the use of the URI that identifies a DC
property as a XML Namespace item - for which XML Schema processing
places a stricter demand on.
Has anyone given thought to this?
2. Rec 3. should encode properties as XML elements and values as the
contents of those elements.
The example shows the "values" as plain strings. My interpretation of
this recommendation is that it does not precluded structured values as
well (even though the examples don't show it.).
That is, it is is not a violation of this guideline to do something
like:
<dc:creator>
<foo:personalName>Fred</foo:personalName>
<foo:email>[log in to unmask]</foo:email>
<dc:creator>
Is this a correct interpretation of this recommendation?
3. Rec 7. encoding scheme
Is it possible to additionally stipulate that the values of the schemes
should be URIs (or QNames?). This way there will be globally unique
scheme identifiers and elminate the possible of duplication and
conflicts.
That is, instead of just:
<dc:identifier scheme="mypartcode">...
recommend that implementors should use
<dc:identifier scheme="http://partsRus.example.com/ns/mypartcode">...
4. Rec 8. element refinement names may be mixed-case
Perhaps this should be clarified to say "Dublin core element refinement
names may be mixed-case", so that it does not have to apply to non-DC
element refinements. This would match the meaning of Recommendation 4,
which applies for DC element names only.
Hoylen
--
______________________________________________ Dr Hoylen Sue
[log in to unmask] http://www.dstc.edu.au/
DSTC Pty Ltd --- Australian W3C Office +61 7 3365 4310
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