Re: boolean datatype ... wtf?

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? Received on Wed Oct 06 2010 - 21:38:48 CEST