Re: NULLs: theoretical problems?

Jan Hidders wrote:
> On 25 aug, 16:32, "V.J. Kumar"
> > Clearly, 'def(x):(x or not x') is allowed [...]
>
> ... and is indeed equivalent with 'def(x):true'.

According to your own definition, 'def(x) : f(x)' evaluates to 'false' whenever x is not defined. So f(x) in 'f(x) = x or not x' must be 'false'.

>
> > Likewise, 'def(x):(x or true)'
>
> ... and is indeed equivalent with 'def(x):true'.

This is interesting. Just a little while ago, you complimented Jon for his understanding that 'select * from table where def(x): (x or true)' is equivalent to 'select * from table where x is not null and (x or true) '. Apparently, at the time you thought that 'def(x) :(x or true) ' should evaluate to 'false'. It seems that now you think that it should evaluate to 'true' ! How do you explain this change of mood ?

 >Which nicely
> illustrates that the usual 2VL laws still apply.
>
> -- Jan Hidders
Received on Mon Aug 27 2007 - 05:26:36 CEST