Re: [Scrollkeeper-devel] URN as identifier

[Bob S. <bo...@sc...>]

> From: Dan Mueth <da...@ea...>
> 
> > But I'm not clear where a series ID fits into the OMF
> > metadata DTD.  If I understand you correctly, the same
> > series ID would be applied to every version/language/format
> > of a document in its history, including when it changes
> > hands.  But the OMF <identifier> element is supposed to be
> > unique to each document.
> 
> Right.  So I guess the URN would go in identifier.  This can be done
> without any modification to the OMF I believe.  (Is a URN considered a
> URL?  If not, I guess we should explicitly state that an identifier may be
> a URN.)

Well, if you look at the OMF template at
http://www.ibiblio.org/osrt/omf/cgi-bin/template.pl
the <identifier> element says "(e.g. a URL or URN)".
The DTD uses "url" as the attribute name, but I believe
that should be interpeted as a more general URI.

> eg:
> <identifier>http://www.ldp.org/docs/howto/nfs</identifier>
> <identifier>urn:blahblahblah</identifier>
> 
> If anybody replies to this, let's please start a new thread with a title
> about URN's ;)
> 
> > I would propose instead using the OMF <relation> element,
> > with its url attribute pointing to a series ID.  By that I
> > mean define a seriesID using uuidgen as Dan suggests.  Then
> > the OMF metadata for each document includes
> > 
> > <relation url="thisseriesUUID" status="omf-series-id"/>
> > 
> > This defines a relationship between this document and the
> > series of which it is a part.  Then you could query an OMF
> > metadata collection to select all documents that share the
> > same relation element.  From that you could select specific
> > alternate version/language/format documents.
> > 
> > Would this be a correct usage of the <relation> element?
> > Would it meet the needs of a seriesID?
> 
> I think using a uuidgen code and putting it in RELATION is the way to
> go.  (I was completely overlooking this element.)  I would propose
> breaking RELATION into two attributes:  RELATION.identifier and
> RELATION.seriesid.  The identifier attribute should follow the guidelines
> of the IDENTIFIER element - it can point to any valid URL/URN.  The
> seriesid is the document series id code, obtained from uuidgen.
> 
> It would look something like this:
> 
> -----
> 14.     Relation
>         Label: RELATION
>         Obligation: Optional
>                 RELATION.IDENTIFIER (Optional)
>                 RELATION.SERIESID (Optional)
>         Maximum Occurrence: Repeatable
> 
> Description of the resource's relationship with other similar resources.  
> RELATION.IDENTIFIER is a URL that points to the IDENTIFIER element of
> another resource.  Each instance of RELATION with the RELATION.IDENTIFIER
> attribute links the resource to other resources of similar domain or
> style. RELATION.SERIESID is a string code which specifies various
> instances of a document, such as various versions, formats, or
> translations.  All documents which are related in these ways should have
> the same RELATION.SERIESID.  No documents which do not belong to this
> set should share the RELATION.SERIESID.
> -----

This sounds fine, but I'm trying to understand the
OMF syntax for these.  As I read the existing
OMF specification for VERSION, it has modifiers
VERSION.identifier, VERSION.date, and VERSION.description.
The description calls these attributes.  But the OMF
DTD defines them as child elements of <version>.  I guess the
spec uses the word "attribute" in the general meaning,
not in the XML DTD meaning.  

If seriesid and identifier are children elements
of <relation>, I'm not clear on how the <relation>
XML attributes are used.  Perhaps we should contact
someone at OMF to get clarification on the
expected usage of <relation>?

bobs