# Re: What databases have taught me

From: Marshall <marshall.spight_at_gmail.com>

Date: 30 Jun 2006 12:20:45 -0700

Message-ID: <1151695245.144139.176850_at_75g2000cwc.googlegroups.com>

Date: 30 Jun 2006 12:20:45 -0700

Message-ID: <1151695245.144139.176850_at_75g2000cwc.googlegroups.com>

Bob Badour wrote:

*> Marshall wrote:
**>
*

> > 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.
*

Other question:

given:

f: A, B -> C

is f part of the defintion or A, or of B, or both? What about C?

Marshall