RE: [higgins-dev] Revised Higgins data model goals

["Paul Trevithick" <paul@xxxxxxxxxxxxx>]

Jim wrote:

> 
> >>> "Mary Ruddy" <mary@xxxxxxxxxxxxxxxxx> 4/18/06 5:47 PM >>>
> >A context can have a subcontext (1:1) or multiple subcontexts (1:M)
> >
> >For example, there might be a context associated with a particular
> >system, and a person may be participating with that system in
> multiple
> >subgroups:  a My Base Ball Fan Yahoo group and My Neighborhood
> >Association Yahoo group.
> 
> Ok, my previous understanding of this was that a single Context would
> be presented. The context provider for the "Uber"-Context could be
> configured to virtualize the Uber-Context from the two sub contexts.
> Thus, to the consuming application, it looks like a single Context. In
> the Bandit project, we call this uber-context provider a joined context
> (well, joined realm in our terms). I guess this is a different use
> case.

Yes, there are two distinct use cases. 

(a) where you do what you're doing in Bandit and create a "joined realm". In
this the uber context could be a simple union of all the sub contexts or
some filtered subset or some completely new synthesis. There may or may not
be correlated DigitalSubjects in the constituent contexts. 

(b) In a second use case the same person Entity may have DigitalSubjects in
multiple contexts. They may have a root context with a root DigitalSubject
that consists mostly of references to its other selves (other
DigitalSubjects) in other contexts. In this case you would expect a kind of
attribute inheritance model where the DS in the root context inherited
attributes from its N sub-DS's in other Contexts.

> 
> In the view where there are two related Contexts like the example
> above, is the person (or application) interfacing with Higgins presented
> with one or the other Context and then actively discovers the related
> Context(s)? Just trying to visualize the experience/use case. Trying to
> find the scenario where one will access the set of related context
> information on a Context.

In (b) the "other" (non-root) Contexts are indeed discovered by examination
of the DS in the root context. (This is a case where the root Context itself
might not explicitly have a sub-Context association with the other
Context(s).

> 
> >Or a context created for participation at a conference may be
> structured
> >with subcontexts: one of which corresponds to the person's role as an
> >attendee, one their role as a presenter, and one designed for any
> >visitor to the conference city.
> 
> Is there a goal to have the notion of Context hierarchy in Higgins? Or
> is the space of Context's flat? If a hierarchy can be modeled, how is
> the parent/child relationship indicated (on the context relationship
> element I imagine). Are there use-cases that require a hierarchical
> relationship? Is there a max depth to a hierarchy?

Context hierarchies can be expressed, though other non-hierarchical
relationships are possible. The use cases that motivated this are directory
cases, e.g. an "department" context might have "sub-department" contexts.

<snip>