Re: Do Data Models Need to built on a Mathematical Concept?
Date: 3 May 2003 20:19:13 -0700
Message-ID: <4b45d3ad.0305031919.438d71d2_at_posting.google.com>
> > > What are the flaws and limitations you had in mind?
> >
> > 2. That all values in a column be of the same type.
>
> This is not generally regarded as a limitation. It is like
> saying that addition is limited because it cannot operate
> on dates.
Just as in pure set theory, I want the flexibility that the elements can be anything. But, in the rdb model, that flexibility cannot be fully realized because the type of values in a domain is restricted to some hardware dependent type (ie int, long, date, 50 chars, etc). If I think of a set of arbitrary thing in my mind, I don't think about their type to decide if they can on cannot be included in that set. If the things in a set are of different types, I probably would not be performing operations such as add or average on them. Received on Sun May 04 2003 - 05:19:13 CEST