Re: 1GB Tables as Classes, or Tables as Types, and all that refuted
Date: Mon, 13 Dec 2004 17:01:16 GMT
Message-ID: <41bdcab4.25310046_at_news.wanadoo.es>
On Mon, 13 Dec 2004 08:16:47 -0600, "Dawn M. Wolthuis" <dwolt_at_tincat-group.comREMOVE> wrote:
>> You can have a class named Relation but you can not define a relation
>> type with an OO language.
>
>Again, why not?
Because OO languages lack that feature.
>You cannot really think that my argument here was that because OO languages
>permit me to name a type "Relation" that ...
So which is your argument?
>> You can read the pseudocode I posted.
>
>I've had trouble with my news reader and am getting caught up, so I'll take
>a look.
You replied to that post, but here is again:
var Customers real relation { Code Char, Name Char }
key { Code };
var Orders real relation { Num Integer, Customer Customers }
key { Num };
Here I am using a relvar as a type.
"Orders" is not a relvar, it is a bullshit.
>I'll read your psuedocode, but is there any product you can identify that
>has practical problems because of making this great blunder?
That is what D&D say in their book.
>> In the case described by D&D the confusion between types and relvars
>> is evident, but in many OO apps I have seen the mistake seems to be
>> that the programmers think that the SQL DBMS is only a weird
>> transactional file manager and the information must be managed by the
>> application using network (graph if you prefer :) structures, like in
>> the old days.
>
>You mean the old days when it took a week to write and deploy a new accounts
>payable system?
No I mean the old days when it took many man years to develop a rather simple system. Like with most of the current OO database projects.
>least 6 months now. Yes, I know -- there are problems with those systems
>that we were addressing with DBMS's, but I fear we threw the baby out with
>the bath water (an overly disturbing metaphor, sorry).
Regards Received on Mon Dec 13 2004 - 18:01:16 CET