[thelist] [DB Design] Recursive Directory Structure

Morgan Kelsey morgan at morgankelsey.com
Sat Feb 1 20:48:00 CST 2003


rudy,

> thanks for the plug, by the way   ;o)
>
> can i make one myself?  http://r937.com/sqlate.cfm
>

ok and again. now thats enough link weight for you this week
:p

> the nested hierarchy problem is, i am convinced, a usability problem and not
> one of technical under-the-covers wizardry
>

well, i think it's both really. the under-the-covers-lizardry is easier to solve
than the usability though (for me anyway)

> yeah, there are ways of making tree retrieval perform really well, and .jeff
> will be along shortly, i'm sure, to explain his augmented version of celko's
> method (i *still* have no clue how to populate and maintain it)
>

i too, have no idea how to populate celko's left/right nested set model.
that i will readily admit.
in fact, i've yet to meet anyone who can convincingly (i'm sure they're out there,
but they don't hang out where i do).

.jeff's tree/level method though, i found very easy to understand once i worked
with it for a while. so easy, you can change the tree sorting right in the table
without
going bonkers.

> but perfomance isn't really the point, is it
>
> once performance becomes an issue, you're talking about a large database,
> multiple levels, and concommitant with this, you typically don't want to
> traverse the entire tree!!
>
> show me a major site where you, as the user, can explode the entire tree
>
> what's your favourite nested hierarchy example?
> dmoz? nope, it's drill down, one click at a time
> about the only example i can think of is a site map, a theoretical explosion
> of all subtrees to their bottom (leaf nodes)
>
> but show me a site map that's more than 4 levels deep that doesn't very
> quickly become too wieldy (or is it unwieldy?)
>

from my years of reading conan novels, i think it's unwieldy.

but, i'm so glad you asked! ;o)

i find google's groups remarkably intuitive to use, especially for a text-driven
menu!
(watch the wrap)
http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&threadm=j8mo3vg2bhulh7kkcqd
p4c5ntdl0epmduu%404ax.com&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26group%3Dre
c.motorcycles

i wonder what they're doing under the covers there....(not the motorcycle dudes,
the google programmers)


nagrom
http://morgankelsey.com/






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