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Re: Canonical DB

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Fri, 23 Jun 2006 11:55:36 +0200
Message-ID: <449bba07$0$31648$e4fe514c@news.xs4all.nl>


Robert Martin wrote:

> mAsterdam said:

>> Robert Martin wrote:
>>> mAsterdam said:
>>>>
>>>> ... "Which (or which types of)
>>>> computations are easier [with a
>>>> navigational structure]?"
>>>
>>> Things like tree searches, graph walks, etc.
>>
>> No, tree searches and graph walks are things
>> you *need* to do (and specify) when all you have
>> is navigational structures. They are part of their cost.
>
> Uh... So in RM there just *aren't* graphs or trees?

Not as an element or basic construct
(not sure I got the question right).

Googling for 'graphs RM' gives
http://www.rm.com/primary/Products/Product.asp?cref=PD1112 ;-), substituting 'relational' for 'RM' made me stumble on http://www.cs.york.ac.uk/cvpr/relational.php

If you don't mind getting your hands dirty: http://technology.amis.nl/blog/?p=1160 mentions some Oracle specifics, in
http://www.dbazine.com/oracle/or-articles/tropashko4 Vadim Tropashko discusses two ways "to model a tree in the database". His new book might be on the way to the stores by now, but I did not find a reference. Joe Celko wrote
http://www.amazon.com/gp/product/1558609202/102-4421784-8373769?v=glance&n=283155

>> Now where is the benefit - what are you computing:
>> Which (or which types of) computations are easier
>> with a navigational structure?

>
> The cheapest path between two nodes through a network graph?

Strange. You construct a navigational thing, a network graph (from what, BTW?), you suggest a problem which is only defined within the context of this construct and you say it easier to compute it with a navigational structure.

?!

This is awfully close to:
Q. "Which (or which types of) computations are easier with a navigational structure?"
A. Those which are easier with a navigational structure.

Do you think the question is not of interest?

>> Until it becomes clear what "the canonical DB"
>> is, and the way and timing to get there
>> explicit, I'll maintain my opposition.
>>
>> "This [asymmetric navigational structure]
>> comes close to first come, first serve.
>> If a new idea is sound at some abstract
>> level it still has to be cost-evaluated
>> against (and possibly rejected just
>> because of) the navigations in place."
Received on Fri Jun 23 2006 - 04:55:36 CDT

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