Re: DB clasical structure violation

From: Bob Badour <bbadour_at_golden.net>
Date: Fri, 12 Jul 2002 22:57:11 -0400
Message-ID: <6IMX8.1178$gx7.518254724_at_radon.golden.net>


Most of the discussions I have seen regarding RDBMS vs. OODBMS centered around physical independence and logical independence, which have nothing to do with ACID properties per se. ie. they are orthogonal issues.

I am curious why you think the debate centers around transactions?

"David Cressey" <david_at_dcressey.com> wrote in message news:hS%R8.31$0U1.3212_at_petpeeve.ziplink.net...
> > And why would you suggest defective technology that was discarded 20
years
> ago?
>
> I agree with the point that hierarchical or network databases are worth
> examining. The gradual replacement of hierarchical and network DBMS
> packages by relational DBMS packages is actually an interesting history.
> It's oversimplifying to say that all those earlier databases were simply
> "defective". Many of them were quite solid. In fact, there are still
> applications today that are running under "pre relational" DBMS packages.
>
> I got into databases just when relational was becoming popular, myself.
So
> my contact with pre relational DBMS packages is limited to what I learned
> from colleagues. I'm thinking of VAX DBMS. Although I never built
> anything in VAX DBMS, I know it supported atomic transactions and
concurrent
> users, and did so very well. I'm not sure, but I believe it also had good
> mechanisms to support database backups. The network databases that ran on
> IBM mainframes were as robust, or even more so.
>
> What's the point of this, some 25 years later? Merely this: that there
are
> some features of DBMS packages that were treated as minimal features to be
> even considered a "serious database package" that predate widespread
> acceptance of the relational model. The idea that each user is entitled a
> transaction environment that is atomic, consistent, isolated, and whose
> outcome is durable (acronym ACID) had already been accepted in the pre
> relational era.
>
> When relational databases came into their own, the best of the breed
> offered all of those features of the pre relational state of the art,
except
> for those features that were fundamentally obviated by the relational
model
> itself. In those cases where the old feature made no sense in conjunction
> with the relational model, the best of the breed offered other features.
> The flexibility and power of those new features accelerated the acceptance
> of the relational DBMS packages.
>
> Now sometimes the debate between RDBMS and OODBMS enthusiasts starts to
> hinge on differences like multi-user concurrency and ACID instead of on
> differences between the two data models. At that point, it becomes
relevant
> to point out that features like ACID have already survived the migration
> from one data model to another, and it's possible, even likely, that they
> should do so again.
>
> Regards,
> David Cressey
>
>
>
Received on Sat Jul 13 2002 - 04:57:11 CEST

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