[XESAM] Ontology sketch. Feedback needed.

[Evgeny Egorochkin]

On Thursday 31 May 2007 00:25:14 jamie wrote:
> On Wed, 2007-05-30 at 18:51 +0300, Evgeny Egorochkin wrote:
> > Hi all,
> >
> > I'd like you to take a look at the ontology sketch
> > http://www.freedesktop.org/wiki/PhreedomDraft?action=AttachFile&do=view&t
> >arget=viz.png
> >
> > It's not complete. Some fields/classes are dropped intentionally.
> > I'd like to hear some feedback first.
>
> thanks for this
>
> changes I would like:
>
> 1) my pref is for something a bit simpler with a lot of the intermediate
> categories removed (IE Visual, Media, Message, Source cats)

Visual category is useful e.g. for file managers to display visual content 
dimensions regardless of type(image/photo/audio)

Message is an anchor for IM messages, not yet implemented. Also, it may be 
extended with more properties. This lets you specifically search for either 
email, Jabber, IRC communications or search all your conversations regardless 
of type.

> 2) The category User does not make sense. User metadata should be
> applicable to all so best in content if you ask me

The destinction between content, source and user is like this:
 *embedded in the file/data object contents
 *external, provided by filesystem/container
 *external, provided by user/annotation apps etc. these maybe stored in e.g. 
filesystem extended attributes and may be stored in a separate db e.g. some 
music app maintaning ratings, usage stats, tags etc for files, but not 
storing the info directly in files.

If we don't find a case for subclassing User category, it will be merged. For 
now it serves to visually separate content- and user- provided data. Probably 
user data will be merged into Source.

> 3) Content itself seems too file specific to be a top level parent of
> all the entities. I think DC and User metadata should be there with
> maybe a FileContent object providing more file specific details

Valid argument, it's still not clear how e.g. Contacts fit the Content class.

> 4) I dont like using one metadata name for several differing purposes.
> EG Email should have an Email.Sender and not a Content.Author (although
> Email.Sender can subclass Content.Author or even better DC.Author)
>
> I would like to see DC metadata at the top with it being abstract and
> most of the other metadata subclassing it. EG we would have
> Document.Author subclassing Dc.Creator etc.
>
> Trying to share metadata names across categories tend to make it much
> harder to read IMO hence better use of subclassing and unique names
> should improve it.

See my Xesam core+convenience proposal in another e-mail.

> Audio needs some Metadata and Contact should use the standard vCard spec
> fields as this is what Evolution Data server uses.

For audio, will do. 

For Contact, will add some stuff. vCard is a good point of reference, but it's 
horribly outdated. AFAIK It doens't support IM services, net phone and 
videophone services. Yey, we must be mapping-compatible with vCard since it's 
still widely used.

--Evgeny