Re: Pizza Example
Date: Mon, 19 Apr 2004 13:46:36 GMT
"Anthony W. Youngman" <wol_at_thewolery.demon.co.uk> wrote in message
> I was thinking in terms of EAR - entity attribute relationship. How does
> the database know the difference between a table that describes an
> entity, and a table that describes a complex attribute of that entity
> (that has to be in a separate table because an entity can have multiple
> instances of it).
It doesn't. That's the point.
> I wasn't trying to model language, I was just making the point that
> language has words that represent something that has physical existence
> (nouns), and words that describe what that existence is like
> (adjectives). Relational theory uses tables to do both these tasks, and
> has no way of telling which task any individual table is fulfilling.
Right. That's the point.
> Okay, MV can't tell for certain, but it's a fairly safe bet that any
> random table is fulfilling the "noun" role not the "adjective" role.
That's not a safe bet, nor is it one you even need to make. That's the root of the E-R nonsense.
> And, for example with optimisation, if you gamble on that being the case
Discussions of gambling in the context of data design are somewhat
> then you will win big nine times out of ten.
Discussions of gambling in the context of data design are somewhatmisplaced. Last I knew, we were trying to create order from chaos, not systematize the chaos.