Re: Logical equivalence of simple and complex types under the relational model?

On Wed, 08 Dec 2004 09:37:04 GMT, "Dan" <guntermann_at_verizon.com> wrote:

>> Databases, databases.
>
>I am not exactly sure how to interpret this reply. Are you suggesting a
>unity between a scalar type system provided at a lower level (e.g. machine
>level or OS level) and the logical RM as managed and presented by software,
>particularly the DBMS?

No, I was speaking loosely. "To have" is a very flexible verb. What I said was intentionally vague, but not incorrect.

I wil try again: DBMSs should implement rich type systems.

Of course "rich" is also a vague word.

>What exactly do you mean by "unity" of a scalar type system, the RM model,
>and databases (in contrast to DBMS's)?

Only between the first two.

By unity I mean that the RM can't exist without a scalar type system. An open ended scalar type system is a fundamental part of the RM.

This debunks the "atomicity" definitions based on the separation between the scalar type system and the "relational system".

Regards Received on Wed Dec 08 2004 - 13:44:54 CET