Re: 1GB Tables as Classes, or Tables as Types, and all that refuted
Date: Thu, 9 Dec 2004 17:44:45 +0100
"Alfredo Novoa" <alfredo_at_ncs.es> s....
> On Tue, 7 Dec 2004 18:33:27 -0600, "Dawn M. Wolthuis"
> <dwolt_at_tincat-group.comREMOVE> wrote:
>>So, the 1GB has nothing at all to do with using a class to define a
>>type, such as "Person" -- is that correct?
> It is not possible to use a class to define a relation type, but the
> 1GB has nothing to do with defining a class such as "Person".
WHY is it "not possible to use a class to define a relation type" in the sense I'm quite sure Dawn refers to: In the same sense as we use an Entity in ER-modelling to define a relation (intentionally loosely speaking, you know ....)?
>> Then if a variable is declared
>>to be of the type Person, does the 1GB refer to that situation?
> No, it refers to the products that mix classes and tables.
> You only have to review the first chapter of TTM to see that.
TTM does appear to talk theory, not products. Anyway, this thread is about Mr. Gittens critique, and that's certainly not about products.
>>I guess I'm
>>asking for more precision in stating what practical is being identified
>>the 1GB. It seems like it is a flap about how one person says, for
>>"relation" when they really mean "relation variable" (translated to OO
> It is about existing products, but I don't use such products.
You don't use existing products :-)
> Fortunately OODBMSs are almost dead, but it is probable that we still
> can find the 1GB in some OR Mappers.
>>the "cause of many confusions". My question is where the blunder really
>>I think I posted a question on this a year or so ago too and I still don't
>>see a practical blunder
> Because it is probable that you are not using a product that makes
> such blunder.
Why shouldn't Dawn be able to see what you see without using such products, when you seems to be able to do it without using any products?
>>Date seems to argue that there is a practical problem in this mix. Do you
>>think there is?
> Of course there is, but only if you use an OODBMS or an OR Mapper.
So in a RDBMS there is no GB in equating class with relvar? Received on Thu Dec 09 2004 - 17:44:45 CET