[daisy] [new feature plan] hierarchical fields

[Bruno Dumon]

On Wed, 2006-08-09 at 09:15 -0400, Thomas, Mark - BLS CTR wrote:
> Bruno wrote:
> > A new feature we're planning to add to Daisy are hierarchical fields.
> > I'll jump right away into explaining my current ideas about this.
> > 
> > A hierarchical field is a field whose value is a hierarhical 
> > path (an ordered set of values), typically selected from some 
> > hierarchy (a hierarchical selection list). In our case, the 
> > actual value of the field would be the complete path to the 
> > selected node in the hierarchie. For example, take this hierarchy:
> > 
> > A
> >   B
> >   C
> >     D
> >     E
> > 
> > If the value 'E' is selected from the hierarchy, the actual 
> > stored field value would be the path /A/C/E. This makes that 
> > hierarchical fields are very similar to multivalue fields. 
> > However, we want the hierarchical fields to also support 
> > multivalueness, so it's a bit like we need two-dimensional 
> > multivalue fields.
> 
> This sounds interesting. Do you have a particular use case in mind where
> this would be useful?

It can be useful in cases where you want to assign a document to a
hierarchical category. Since things are often organized in hierarchies,
this can be useful for lots of things.

For example, one could make a hierarchical classification of types of
software, and then create documents describing software packages and
assign them to a place/s in this hierarchy.

-- 
Bruno Dumon                             http://outerthought.org/
Outerthought - Open Source, Java & XML Competence Support Center
bruno at outerthought.org                          bruno at apache.org