Re: boolean datatype ... wtf?

On Oct 6, 1:25 pm, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
> paul c wrote:
> > On 06/10/2010 11:03 AM, Bob Badour wrote:
>
> >> paul c wrote:
>
> >>> On 06/10/2010 6:51 AM, Bob Badour wrote:
>
> >>>> Null is an indicator that evaluates to NULL or NOT NULL. ie. it is a
> >>>> boolean.
>
> >>> This makes me want to take another stab at an old point. I think it is
> >>> a boolean and how it's constructed within a relational db seems
> >>> crucial which I'd say it can't be in any logical way. Maybe this is
> >>> part of what what Erwin S means too.
>
> >>> It's reminiscent of how Table_Dee has a maximum cardinality of one,
>
> >> You misspoke. Table_Dee has a cardinality of exactly one. Table_Dum has
> >> a cardinality of exactly zero. Nilary relations have a maximum
> >> cardinality of one and a minimum cardinality of zero.
>
> > yes, the word 'maximum' here was pointless, albeit not untrue.  What is
> > a 'nilary' relation, don't remember that term, is it one with no
> > attributes?
>
> Yes. Nilary (perhaps more common as nullary?) is to unary as unary is to
> binary and as binary is to ternary.
>
> http://en.wikipedia.org/wiki/Arity

Thanks. It doesn't seem to mention 'nilary' but does mention 'nullary' and 'niladic' which I take to be the same.

We're all prisoners of the lingo we know. I never learned much SQL but when consumer cpu's started to proliferate I started to use 'C' because I didn't want to learn a bunch of different assembly languages. That's the first time I ran into 'null' and for me the meaning was extremely narrow, just referring to a pointer that didn't point to anything useful. Old assembler people would have equated that with a 'flag', which is why your mention elsewhere of it being a 'designator' didn't confuse me. They were all used to core/storage dumps where no matter what the cause the first step was always to take a quick look at the register contents. Often there would be register that had a value which was obviously the hex value of some fourcharacter  ebcdic or ascii sequence and one could a lot of time by not reading the rest of the dump. I still haven't got used to the idea that 'null' can be a value in the same context that the number three might be a value. With any luck, I never will.

(Sending this msg is painful. Local internet supplier (BC Telus) has dropped nntp. This google groups I/F sucks (a word I hardly ever use but it seem to suit here). For me the most obvious feature is missing - the ability at first glance to see the latest individual post subjects, author and date/time and number of lines. Can't figure out how to have this google web interface do the same, seems I have to start at the 'beginning' and keep clicking 'newer' until I get to the latest post. Just another example of the internet going backwards, not unlike other worldly phenomena but kind of ironic for a fairly modern innovation to do that.) Received on Thu Oct 14 2010 - 20:23:36 CEST