[Zope-CMF] Extensible Metadata

[ctmobile@gocept.com]

On Tue, Aug 06, 2002 at 09:24:17AM +0800, Tim Hoffman wrote:
> Hi Christian
> 
> I have been thinking about this problem for a while, and done some
> fiddling, but haven;t had enough time to devote to either a write up 
> or finishing any code.
> 
> My thoughts are that the current metadata tool needs to be replaced.
> Along with defaultDubinCoreImpl (which is what was intended by putting
> it in CMFDefault rather than core ;-)
> Despite what Dieter says about what you can do with the current tool, it
> is pretty crude and basic.

Yes. I still didn't find a way to introduce *one* new field to the set 
of metadata, without modifying the DublinCore implementation.
> 
> My thoughts are along the lines of a new metadata tool which has the
> following features. (I think it could be built using formulator so
> form generation can be also made easier.)
> 
> What I would like are
> 
> 1. The tool where possible preserves all of the existing portal_metadta
> interfaces. 
> 2. Metadata name spaces, essentially the tool comes with a single
> default name space for DublinCore. If you need additional set's of
> metadata .e.g. AGLS you can add a new names space. 

This doesn't sound good to me. Actually you have a set of metadata which 
involves the same data (e.g. Location), so why should you enter this data
twice? One reason may be, that the different metadata spaces have a different
definition of location, but if every object may have a different kind of 
location description, we lose the effect of metadata: easy classification.

I think you could define a single space for all metadata, but have a set
of views on that, e.g. one view offers you the DublinCore, the next one 
may offer "AGLS" ... . You got the point.

> 3. Each namespace can be defined by creating a namespace object which
> inherits from Formulator.
> 4. Each field/attribute of the metadata namespace could be defined as a
> formulator field.

I don't know if that's needed. I never touched Formulator, as I have my
own tools.

> 5. I would like to be able to say specific namespaces may be mandatory
> for specific content types, but unnecessary for others.

Actually, this is what the current metadata tool seems to be aiming at.
You can set constraints on fields. Not on namespaces, but see my earlier
comment on the namespace issue.
> 
> I have a some of this working (only as a proof of concept) Preserving
> some of the old metadata tool interfaces are a bit of a pain.
> 
> Just my 2c worth
>
Thanks,
Christian