Re: OO and RDBMS

merlin(dot)moncure(at)rcsonline(dot)com ("Merlin Moncure") writes:
> As a follower of the advocacy list, I feel compelled to make a few
> observations about the above post. Perhaps I'm speaking to the choir,
> but I am passionate about this subject, and I always astounded about the
> sheer volumn of misinformation that abounds!

I browsed the Purveyor posts on /., and there certainly were some good
comments made.

There are several drawbacks to the would-be-superior system

- It only provides fairly weak transactional "guarantees."

Yes, any one transaction can can be rolled back, but it does
not appear to extend past that. Which is fine for a single
user system, but not for multiuser.

- It doesn't do anything about managing domain typing.

The increasing support in PG7.4 for CREATE DOMAIN is something that
should surely be trumpeted as a strengthening of relational
modelling. Purveyor... Doesn't do this...

- One of the most significant merits of the relational model is that
it allows data access paths that weren't necessarily planned for.

If I need to look at all the transaction records generated between
March 10th and April 15th, that have some other oddball
characteristics, I need only /describe/ the query, and a relational
system can do the query. It may not be particularly efficient in
the absence of a useful index, but that may well not matter.

In contrast, "object systems" are by and large a throwback to the
Network model, where queries require writing a program to navigate
through the paths provided by the indices. Which is _blazingly_
fast, if the pre-planned paths are the ones you wanted. But if you
need something "oddball," the result may be a query program that is
both inscrutable and slow.

What is unfortunate is that it looks like they have implemented
something that's pretty neat that is probably pretty useful for
embedding a sort of "database" support into applications in some
dynamic languages. But since they _dramatically_ oversell it,
apparently because the producers are "youths" that don't have enough
perspective to grasp that other systems _do_ have merits, it's likely
to get treated as worthless because of the over-sell.
--
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