Re: Very simple question to relational theorists.

Philip, thank you for answer. Unfortunately I am not so sure about my knowledge as you are (that's why I'm asking here).

> From your messages and papers and quotes and misquotes, you don't understand the relational model.
May be.

>SQL is a mess as a programming language and a mess at being relational.
Yes.

>The OMG and O/R camps do not understand the relational model; SQL object extensions are partly not relational, partly messily relational.
Absolutely

>Your proposals are essentially these.
No.

> You need to learn about the relational model before you try to unify it with something.
May be (to learn to learn and to learn :) ) .

> The formal system maps relations to relations but also predicates to predicates. You only understand the relation part. You do not understand the predicate part. You do not understand the connection between the parts. So you do not understand the formal system.

I really think that there is no two different parts. Each relation has predicate by default. When relational operations are performed on the relationas their predicates are operated too. I cannot imagine how it is possibly to operate on relations without operations on their predicates. Also there is no possibility to change a predicate of existing relation.

But I'm just asking about formation rules which allow names of attributes be formed.

It seems that you think that a predicate IS a meaning.

Please, answer me before further discussion - will I change predicate when I change(rename) attribute of some relation? Received on Thu Sep 06 2012 - 10:53:17 CEST