Re: Example of expression bias?
Date: 21 Jun 2006 01:44:50 -0700
paul c wrote:
> Tony D wrote:
> > ...
> >> A data type in RM = (a domain1 to draw values from) + (restrictions
> >> implemented on domain1 --> domain constraint) + (operators that can be
> >> defined using that data type)
> >> ...
> > This may be one definition of a data type (not quite one I'd accept, as
> > we've thrashed over elsewhere), but there is nothing particular to RM
> > about this.
> > ...
> "domain constraint" seems an uncommon term to me because we usually talk
> of constraints on relations. but I often puzzle over constraints,
> thinking that they could be as fundamental as any other notion, e.g.,
> once one arrives at a similar conception of relations to Codd's, one
> could view everything that one does with them as either adding or
> subtracting constraints.
Meant as constraints applied to values extracted to from a domain. In ensemblist mathematics, one could perceive a data type as a subtype derived domain. (restrictions applied on values drawn)
Received on Wed Jun 21 2006 - 10:44:50 CEST