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Re: What databases have taught me

From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Fri, 30 Jun 2006 19:00:15 GMT
Message-ID: <3xepg.4234$pu3.99526@ursa-nb00s0.nbnet.nb.ca>


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 - 14:00:15 CDT

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