Re: c.d.theory glossary - RELATION

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Fri, 30 Apr 2004 18:20:40 +0200
Message-ID: <40927ce3$0$557$e4fe514c@news.xs4all.nl>

x wrote:

> mAsterdam wrote:

>>>>>If yes, those  _things_  are explicitly or implicitly represented
>>>>>in relational model ? And by what ? Why not otherwise.
>>>>
>>>>Assuming yes about the first question:
>>>>'represent' would be 'explicit', imho.
>>>>By what? By the propositions (by means of the predicates).
>>>fact: John likes Mary.
>>>Which proposition represents John ?
>>
>>The proposition "John likes Mary" represents John.
>>Indirectly, but explicitly. Like so:

>

>>"John likes Mary" would be in the body of a relation.
>>It's predicate would be (short) "<Person> likes <Person>".

>
> Why we don't directly represent John in the database ?

Because of the context we were discussing this in. We were discussing RM.RELATION vs ER.RELATION.

AFAIK this (see previous post) is the way RM goes about representing facts, ER has no way of showing the facts in the body of a RM.RELATION, it only represents what would be in the heading.

>>Are you sure he likes her?

>
> Well, I don't know if he is sure ...
> Are we talking about same people ?

heh. Received on Fri Apr 30 2004 - 11:20:40 CDT