Re: Question on Multiplicity

"jason.glumidge_at_gmail.com" <Jason.Glumidge_at_gmail.com> wrote in message news:1130334318.730554.140170_at_f14g2000cwb.googlegroups.com...
> Imagine you were knocking up a simple table of animals and their
> predominant colors. Something of the order:
>
> ----------------------
> animal | color
> ----------------------
> swan | white
> lion | yellow
> oranguatan | orange
> ----------------------

To see what is going on here, ask yourself what sentence you intend to plug these words into to form true statements. (i.e. what is the predicate?) Here are some suggestions:

All <animal> are <color>.
Food for <animal> is stored in warehouse zone <color>.

A <animal> can be entirely <color>.
A <animal> is >93% <colour>.
A <animal> can be partly <color>.
A <animal> can never be <color>.

> Consider also that some animals that have multicolored fur. For
> instance a zebra is black and white. Keeping the table nice and
> normalized yields:
>
> ----------------------
> animal | color
> ----------------------
> swan | white
> lion | yellow
> oranguatan | orange
> zebra | black
> zebra | white
> ----------------------

It would appear that you have a table but you don't know the predicate, or you know the predicate and the table is wrong.

[snip]
> Now my question is am I missing anything - is there any method of
> making this distinction without having to introduce a new reference
> column to resolve the ambiguity?

You'll need to decide on the predicate, and it's not clear to me that you have one. You might even find you need multiple predicates (and multiple tables).

Roy Received on Wed Oct 26 2005 - 18:07:31 CEST