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pcplantdb - Re: [pcplantdb] Object oriented model reprise

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  • From: John Schinnerer <john@eco-living.net>
  • To: pcplantdb@lists.ibiblio.org
  • Subject: Re: [pcplantdb] Object oriented model reprise
  • Date: Sat, 04 Sep 2004 16:04:42 +0000

Aloha,

There are design decisions needed about where the display
method fits. We can have
display(plant)
or plant.display()

In the former the display method and data are separate
the plant object does not know how to create the web page about it.
This makes it easier to use a variety of different
ways to display a plant. We might want to create a
PlantDisplayer class and sub classes of this handle the display,
viz htmlPlantDisplayer, xmlPlantDisplayer, touchgraphPlantDisplayer.

I have been assuming that the front end will handle these decisions.
The back end would have an API that's all about taking in queries and returning the requested information in client-independent form.

The clients would decide what/where/how to re-present that info to the user who made the request.

The DB and related back-end code - regardless of what it is - would communicate directly with each other in whatever way was most efficient. Probably not XML!

XML would be for passing the info to and from the client apps and the DB/backend.

Well the notion of a plant species is an abstraction.

Yep. Possibly useful, possibly pathological.
As with all else, it's how we use 'em and/or value 'em that has consequences.

It represents a whole set of individual plants
which are all different in subtile ways. Their simalarities
make the plant species a (mostly) useful abstraction.

IMO important to note that the most commonly applied set(s) of plant "similarities" are only one of an infinite number of sets of observable similarities.

For example cruciferous plants are considred "similar" based on their X-shaped parts. That's one arbitrarily chosen similarity that has become "the" similarity that matters.

Cabbages and onions are not considered "similar" under that system - but under a system that looked at e.g. sulfur content as a point of similarity they would be.


I'm sure that there is some quote out there saying
computer science is the science of constructing
useful abstractions.

There is now! ;-)

--

John Schinnerer - MA, Whole Systems Design
------------------------------------------
- Eco-Living -
Whole Systems Design Services
People - Place - Learning - Integration
john@eco-living.net
http://eco-living.net





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