Re: What databases have taught me

From: Bob Badour <>
Date: Fri, 30 Jun 2006 19:00:15 GMT
Message-ID: <3xepg.4234$>

Marshall wrote:

> Dmitry A. Kazakov wrote:

>>On 30 Jun 2006 08:39:09 -0700, Marshall wrote:
>>>>Side note: in a strongly typed language "extension" of an operation can be
>>>>accomplished only through an "extension" of the type (actually a class of).
>>>>This happens by adding a new type to the class, so that the operation
>>>>extension be defined on that new type.
>>>I believe you are descring OO here, yes?
>>Actually any typed system with user-defined relations on types, I don't
>>think that it is any specific to OO. Nothing prevents RM from allowing
>>polymorphic values in tuples. Also tuples themselves could be made
>>polymorphic as well (to support mixed logics, for example, or to attach
>>some constraints etc).

> Mmmm, what I was trying to point out is that it is a somewhat
> OOish idea to consider functions on a type as part of the
> definition of that type.
> Given a set A, and a set B.
> Given a function f: A -> B
> We would not *necessarily* consider f as part of the definition of A.

I would. I wouldn't necessarily require all operations defined on a type be declared to the dbms, but the type is a set of values and a set of operations on those values. Received on Fri Jun 30 2006 - 21:00:15 CEST

Original text of this message