Carl & all,
I agree with Dan v. much regarding extensions - I'm currently working on an
XML representation of the UK e-Govt metadata standard (e-GMS), which is
built on DC. The extensions to DC in e-GMS are essential to its user
community - yet it's also clearly desirable to have an easy walk-through to
DC in XML.
Experience with a prototype earlier this year showed us that characterizing
specialized-dc-style metadata using W3C schema led to a choice in practice
between v. light validation and v. restrictive syntax (a third option being
a seriously over-complex schema which would be v. bad to maintain).
At present, I have a marker in for a future version of the e-GMS/XML spec to
have an additional part to cover DC interoperability. My working assumption
is that an explicit dumb-down (forgetful and faithful) conversion will be
required to go from e-GMS XML form to DC; I am hoping that it will be
relatively simple. I also hope that the XML structures involved will not be
over-dependent on the detailed characteristics of W3C schema as opposed to
other XML schema approaches. Bearing in mind the v. long working life of
many public sector documents, the strategy for e-GMS is to stick to XML
structures which are likely to be straightforward to validate using a range
of approaches (eg as currently included in the ISO DSDL work).
I look forward to seeing the schema asap.
Regards,
Ann W.
-----Original Message-----
From: DCMI Architecture Group [mailto:[log in to unmask]]On
Behalf Of Dan Brickley
Sent: 12 July 2002 12:29
To: [log in to unmask]
Subject: Re: Mixing dc qualifier with other namespace's qualifier
allowed ?
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hi Carl,
Carl Lagoze wrote:
> There is currently no DCMI recommended XML schema for qualified Dublin
Core. A group (of which I am a part) is finalizing a recommendation in this
are, which will be released for discussion in the next couple of weeks.
Interesting. Are your discussions publically readable anywhere? Is this
OAI work?
> The XML snips you have included below does not conform to this schema.
Furthermore, the proposed schema does not accommodate the notion of
additional attributes that you use in your examples. While it indeed may be
useful for individual communities to employ such additions, easy
interoperability amongst parties relies on reasonably strict common
languages (defined by schema). This is not easy if each communicating party
mixes in elements are attributes that are unique to their application.
Yes, predictability is nice. But the kind of rigid restrictions you seem
to be advocating (difficult to tell without seeing the schema) come with
a different associated cost: others can't easily re-use it, so they go
off and create their own XML Schemas, fragmenting the information space
still further.
One trick (there are others) for hanging things together in such an
environment is to make sure that instance data for all such XML Schemas
also parses as RDF. That way, RDF apps can merge from all sources,
regardless of the XML Schema that policed them. Is this what you're doing?
Dan
>
> Carl
>
>
>>-----Original Message-----
>>From: Piccand Régis [mailto:[log in to unmask]]
>>Sent: Friday, July 12, 2002 5:25 AM
>>To: [log in to unmask]
>>Subject: Mixing dc qualifier with other namespace's qualifier
>>allowed ?
>>
>>
>>Hello all,
>>
>>I usually use my own DCMI XML schema, which contains dc
>>qualifiers, to assign metadata to electronic documents.
>>
>>Here is an abstract :
>>
>><dcmi:relation qualifier="isPartOf">Batch55</dcmi:relation>
>>
>>The namespace I used up-to-now is "dcmi" and points to "our"
>>URI ; we will consider shortly revising this to stick to the
>>actual recommendation, but it we are not yet ready for this.
>>
>>I am now facing a case where I'd like to add a new attribute,
>>say "positionInBatch" to the dcmi:relation element which would give :
>>
>> <dcmi:relation qualifier="isPartOf"
>>positionInBatch="12">Batch55</dcmi:relation>
>>
>>To achieve this, I have created a new schema which declares
>>the simple type for "positionInBatch", and imported it in my
>>usual DCMI schema, with its own namespace ("dcmieav" in the
>>example below).
>>
>>The relation element is declared in the dcmi schema which
>>targetnamespace is "dcmi" and looks now like follows :
>>
>><xs:element name="relation">
>> <xs:complexType>
>> <xs:simpleContent>
>> <xs:extension base="Relation">
>> <xs:attribute name="positionInBatch"
>>type="dcmieav:PositionInBatch"/>
>> </xs:extension>
>> </xs:simpleContent>
>> </xs:complexType>
>> </xs:element>
>>
>> <xs:complexType name="Relation">
>> <xs:simpleContent>
>> <xs:extension base="xs:string">
>> <xs:attribute name="qualifier" type="QualifRelation"
>>use="optional"/>
>> </xs:extension>
>> </xs:simpleContent>
>> </xs:complexType>
>>
>>
>> <xs:simpleType name="QualifRelation">
>> <xs:restriction base="xs:string">
>> <xs:enumeration value="isVersionOf"/>
>> <xs:enumeration value="hasVersion"/>
>> <xs:enumeration value="isReplacedBy"/>
>> <xs:enumeration value="replaces"/>
>> <xs:enumeration value="isRequiredBy"/>
>> <xs:enumeration value="requires"/>
>> <xs:enumeration value="isPartOf"/>
>> <xs:enumeration value="hasPart"/>
>> <xs:enumeration value="isReferencedBy"/>
>> <xs:enumeration value="references"/>
>> <xs:enumeration value="isFormatOf"/>
>> <xs:enumeration value="hasFormat"/>
>> </xs:restriction>
>> </xs:simpleType>
>>
>>In my instance document, where the DCMI schema is imported, I
>>can legally have :
>>
>> <dcmi:relation qualifier="isPartOf"
>>positionInBatch="12">Batch55</dcmi:relation>
>>
>>where "qualifier" is of a DCMI namespace and
>>"positionInBatch" is originally from a "dcmieav" namespace.
>>However, is this "legal" in a DCMI point-of-view ? Is the
>>mixing of attributes from namespace other than DCMI allowed ?
>>Thanks in advance for any help or pointers, Régis Piccand
>>
>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
iD8DBQE9Lr1hPhXvL3Mij+QRAgt2AJ9AyXw4o4Dt2gPbc+EUUxhpLhxlCQCgprjU
syZM7cX3pcl3dzAdkVOb45g=
=+Pxv
-----END PGP SIGNATURE-----
|