[Zope-CMF] Re: Metadata Toolz

[sean.upton@uniontrib.com]

Some thoughts about metadata:

- Every type of component in a CMS has metadata:
	==> Content objects have metadata
	==> Metadata can have metadata too:
		==> Relationships between content objects (which are both
content, in a sense, and rich metadata as well) have metadata
	==> Views (which are also content) have metadata about them
	==> Software assets have metadata
	==> Workflow: Activities and States have metadata

- A metadata system should be storage/implementation-actor agnostic, and
support the ability for objects to implement their own metadata, or not (and
have a tool act on their behalf to defer to for implementation).
	==> There are times when it is appropriate to derive metadata from
content objects themselves (for example, in the case of content objects
created in external systems that have metadata prior to ever being in Zope).
A good example is relationships: a news article may come from a media
production system and be imported into Zope/CMF with a reference to an
associated image.  In this case, there is a relationship intrinsic to the
said document, but there might be other relationships best managed outside
the object.
	==> In other cases (often), metadata should be stored outside the
object, and methods should be implemented on behalf of a content object, not
by it.

- I think DCMES is a good core set that should be the minimum price of entry
for all content objects; if they don't implement this on their own, they
would do it with help from a tool.  Mapping of other metadata schemes to
DublinCore should be simple (perhaps drop-in schemas with scripts that
implement DublinCore methods from other metadata sets, as well as mappings
to obtain metadata-from-data); Tres is right, though, that mapping might
involve "loss of fidelity" (for example, even with full implementation of DC
Relation Qualifiers, this alone can't express, very meaningful, rich
information about relationships.

- I'm starting to think that every component of the system should have
metadata associated with it; even the relationships between objects and the
activities associated with them; even the software components and "view"
objects that render compositions of objects should have metadata.  Relevant
standards for each of these types of components should be determined, and
all should map to one basic set (DCMES+Qualifiers, IMHO).

- DCMES is necessary, but potentially not sufficient for a default set,
there may be a few other core properties for content on top of the DCMES and
its qualifiers (though I am not sure).

Sean

-----Original Message-----
From: Paul Everitt [mailto:paul@eurozope.org]
Sent: Thursday, October 10, 2002 12:42 AM
To: Gitte Wange
Cc: zope-cmf@zope.org
Subject: Re: [Zope-CMF] Re: Metadata Toolz



On lundi, oct 7, 2002, at 15:06 Europe/Paris, Gitte Wange wrote:

> Well I have been thinking about it all morning :-)
> I was thinking about doing something to the metadata tool so it could
> use different metadata implementations (specify them through ZMI). In
> that order you could say that your Images should use DublinCore 
> metadata
> but your media events should use MPEG-7 ... :-)
> Sort of like with the workflow tool ... I think :-))

I'll give fair warning here...if nobody participates in Z3WCM (Zope 3 
Web Content Management), then its metadata *might* look the way I lobby 
for, and that means:

1) There are core metadata items that all "content" must provide for 
(even if there are no values).

2) That core metadata model is spelled d-u-b-l-i-n c-o-r-e. :^)

Of course the metadata model should be extensible.

I'm still confused by the problem, though...is the stuff in media 
events data or metadata?

--Paul


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