From: Daniel DeLorme <dan-ml@...42.com>
Date: 2007-03-29T14:34:47+09:00
Subject: Re: Object/Relational Mapping is the Vietnam of Computer Sci

Austin Ziegler wrote:
>> an OODB can therefore be relational.
> 
> Wrong. This is completely backwards. The relational model can
> *certainly* model an object graph; an object graph is not thereby
> automatically relational. You're assuming that "a therefore b" also
> means "b therefore a" and that just ain't the case at all.

I think *you* have it backwards. All relational models can be expressed 
with an object graph but not all objects graphs can be expressed with a 
relational model. Which is why I said than an OODB *can* be relational, 
not that all OODBs are inherently relational.

> Object database proponents tend to believe that the relational theory
> is ... bunk.

It's not because some OODB proponents are ignorant that it makes OODBs 
an inherently worthless concept. I'd rather base my opinion on my own 
analysis of the potential rather than the claims of the 
proponents/marketers.

> points I mentioned earlier, though (Wikipedia and the c2 wiki) are
> really good and get you ready for understanding much of what Fabian
> Pascal and Chris Date say.

After reading the "Interpretation" part of the wikipedia article I think 
I'm starting to understand your position. You like the elegance of set 
operations, the higher-level abstraction of manipulating relations 
rather than individual rows. Am I right? Well anyway it didn't change my 
opinion. I still believe that:

      tuples of relation == rows of table == instances of class

Daniel