Since theology has arisen, how's this: Object oriented databases are better for this stuff than either hierarchical or relational, precisely for the reasons you outline below.

[By the way, hoping this is not a forbidden commercialism but at least reveals my conflict of interest: we operate the university program for eXcelon, Inc. (formerly Object Design) by which universities can get Object Store, eXcelon [a native XML store], and most other eXcelon products for a total of $650/year. See our web site at www.cs.umb.edu/~serl/odiedu. This is a pretty good way to get into OODB's if you are a university. The program applies in most of the world.]

Bob Morris

Kevin Thiele writes:

Date: Mon, 28 Feb 2000 09:47:10 +1100 From: Kevin Thiele kevin.thiele@PI.CSIRO.AU To: TDWG-SDD@usobi.org Subject: Progressive Revelation

At 15:30 24/02/00 +1100, Eric Zurcher wrote:

...

6. I'm intrigued by the notion of a "Progressive Revelation model"

(footnote 5). It sounds terribly theological - or perhaps that's Thiele-logical? (my apologies to Kevin, but I really can't resist bad puns).

I'm often accused of teleology, but rarely of theology.

Progressive Revelation is perhaps a new way of handling holes in data matrices for random-access keys. The background is this:

The simplest data structure for a random-access key is a fully populated matrix i.e. all taxa are scored for all characters/states. Works well sometimes, especially if the taxa are highly comparable e.g. the species of a genus or the genera of a family.

This structure is problematic sometimes though, for two reasons. Firstly and most simply, you may not have data for all taxa, and need to leave holes in the matrix. Solution is simple - fill the holes with ?s and allow for this in the key program. But it often also happens that some characters are simply inapplicable to some taxa, or (worse) are non-ambiguous for some taxa but ambiguous for others. For instance, stipules don't occur in monocots, stipule-like structures sometimes do but if you try scoring stipule characters as defined for dicots against monocots you run into all sorts of strife because of ambiguity of context. LucID can handle this to some extent using the "present by misinterpretation" score, but the problem is in the character definition, not the score.

...