Re: On view updating

"Tony Douglas" <tonyisyourpal_at_netscape.net> wrote in message news:bcb8c360.0409300058.45425773_at_posting.google.com...
> "Laconic2" <laconic2_at_comcast.net> wrote in message
news:<pvCdnRrp-JR6k8bcRVn-rw_at_comcast.com>...
>
> > Nah! Just back off from the kludge of calling a NULL a "special value".
> > Call it what it is: an alternative to a value.
> >
>
> I don't think I've ever referred to NULL as a "special value", or
> indeed a value of any stripe. Mainly because it isn't. NULL means
> (amongst other possible interpretations) "no applicable value from the
> specified domain". Or just "unknown". Or maybe "not known, but RSN".
> You don't really need NULL anyway; with a decent type system, if you
> need "out of band" markers you can define your own, sensible markers.
> Without even requiring 3VL to handle non-values. Although unknown
> information is always going to be a pain in the proverbial, it doesn't
> make sense to make the problem more difficult by using one (or more !)
> NULL and thence wandering beyond boolean logic.

I am sorry. I didn't intend the implication that you had called NULL a special value. My comment was intended as a general exhortation to the powers that be, and not as personal complaint against you. I should have worded it differently.

I will say that the systematic treatment of nulls is one of the salient differences between "relational calculus" and "the relational model of data". Received on Thu Sep 30 2004 - 14:54:34 CEST