Canonical DB (was: The wisdom of the object mentors)

From: mAsterdam <>
Date: Tue, 20 Jun 2006 20:05:00 +0200
Message-ID: <44983839$0$31637$>

Robert Martin wrote:
> mAsterdam, parafrasing Robert Martin, said:

>> "Applications should not strongly
>> depend on a navigational format unless that
>> format IS the most convenient form for them.":
>> a matter of convenience for some applications
>> at the cost of convenience for other applications.

> And so each application programmer needs to decide
> what form the data is most convient in, and convert
> from the canonical DB form to that convenient form.

This only raises new nuances to my original questions about your statements.

"the canonical DB" is what, and gets designed how? When? To start by converting from it the DB design must be finished before the application design starts - is that part of your method(ology)?

You say "canonical" - is that to avoid one of the terms non-navigational and relational?

You snipped my original questions.
I'll re-state them in the current context this time:

Earlier you said:

"Because it [asymmetric navigational structure] also makes some computations easier."

And I asked "Which (or which types of)
computations are easier [with a
navigational structure]?"

To not let you do all the work:
I'm thinking of regex matching, summary searching. In practice these do get dedicated navigational (on-the-fly or frozen) structures to work on. Are you talking about computations such as those or completely different stuff?

Why did you not (even try to) answer this (to me) relevant question? Do you think it is not relevant?

Also you said:
"An application will often reform data into a non-relational structure that eases computation."

In order to clearly understand what you meant by that, I asked: '"non-relational" as a synonym to "navigational" or did you have something else in mind?'

Same here: Do you think it is not relevant?

Until it becomes clear what "the canonical DB" is, and the way and timing to get there
explicit, I'll maintain my opposition
(which you also snipped):

"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 Tue Jun 20 2006 - 20:05:00 CEST

Original text of this message