Re: Binary Relational Modeling call
Date: Fri, 16 Sep 2011 08:14:45 +0100
Message-ID: <slrnj75tr5.uje.eric_at_teckel.deptj.eu>
On 2011-09-15, Ivan <ivanvodisek_at_gmail.com> wrote:
> "...Relations used in BRM are actually many-to-one relationships. Besides
> their regular use, they can be used to express definitions of tables
> and their columns. It also turns out that many-to-many and one-to-one
> relationships can be represented using BRM relations. Many-to-many
> relationship can be expressed using a complementary pair of BRM
> relations (experienced database users will be familiar with this
> technique). One-to-one relationships can also be expressed in similar
> way like many-to-many relationships, but with some unique constraints..."
If that's a quote from somewhere you should say where.
That quote, and many of your previous posts here, assume that relation
and relationship are the same thing, and in the Relational Model they
are not. Many people assume that the "Relational" in the Relational
Model refers to relationships between tables, but it refers to a
Relation, defined as a set of tuples[1], which in fact corresponds to a
table. Until you sort that out for yourself you will continue to fail to
make sense.
Eric
[1] with various restrictions. Look it up!
-- ms fnd in a lbryReceived on Fri Sep 16 2011 - 09:14:45 CEST