[Zope] [OT] Re: ZOPE IN WINDOWS, ANY WARNINGS I SHOULD KNOW? .RE: [Zope] crystal reports

Aurélien Campéas aurelien.aa@wanadoo.fr
27 Jun 2003 18:44:09 +0200

Le jeu 26/06/2003 à 23:43, Dieter Maurer a écrit :
> A relational database essentially supports a single data type:
> a two dimensional table. 

hmmmmph ! you are not serious, are you ?

I don't know of any RDBMS which doesn't support primitive types (int,
float, bool, char, string).

> The ZODB supports an openly extensible
> set of data types. 

What is more extensible that the combination of primitives types +
relations + inclusion constraints ? 

Lacks encapsulation, inheritance, as in OO ? Hopefully no serious DB
backend provides true OO semantics since those don't exist (OO semantics
are really defined at the level of the language itself). Relational
algebra on the contrary has solid grounds in set and predicate theory.

You can map any "OO model" into the relational model. Not the other way

> This might be considered "less straightforward
> to understand". It definitely is not a flaw.

The flaw lies in this fact : ODBMS are really hierarchical DBMSes, like
the ones of the 60's and 70's that the relational model was supposed to
help throw out of the window.

That's not to say ZOBD isn't neat and usefull, but please. I just hate
when some knowledgeable person spreads FUD on those topics.