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$pu3.99526_at_ursa-nb00s0.nbnet.nb.ca>
>
>
> Mmmm, what I was trying to point out is that it is a somewhat
> OOish idea to consider functions on a type as part of the
> definition of that type.
>
> Given a set A, and a set B.
> Given a function f: A -> B
>
> We would not *necessarily* consider f as part of the definition of A.
Date: Fri, 30 Jun 2006 19:00:15 GMT
Message-ID: <3xepg.4234$pu3.99526_at_ursa-nb00s0.nbnet.nb.ca>
Marshall 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