[XESAM] Ontology snapshot

[Evgeny Egorochkin]

On Thursday 07 June 2007 17:02:22 Fabrice Colin wrote:
> On 6/7/07, Mikkel Kamstrup Erlandsen <mikkel.kamstrup at gmail.com> wrote:
> > To ease the query expansion on the servers each Category
> > will have a property "abstract" that if true implies that objects
> > can not be assigned to this category. In the standard xesam
> > spec non-abstract cats are just the leaf nodes of the cat tree
>
> Are you sure about this ?
> Looking at Evgeny's viz.png diagram, I would think some
> non-leaf categories would be useful, eg Document and Message.

The definition of "abstract category" is a category that's never assigned to a 
file(children used instead), but it still can be queried.

E.g. we can realistically expect that Media category is never directly 
assigned, since we know very well what kinds of media we might encounter and 
have children categories for that.

Also, this information is not essential and only useful to certain 
implementations for performance optimizations. It doesn't introduce any 
limitations/implications.