> =head1 TITLE
>
> Add 'tristate' pragma to allow undef to take on NULL semantics
>
<...>
>
> The C<tristate> pragma allows for undef to take on the RDBMS concept of
> C<NULL>, in particular:
>
> 1. Any math or string operation between a NULL and any other
> value results in NULL
>
Any math or string or logical operation...
> 2. No NULL value is equal to any other NULL
>
> 3. A NULL value is neither defined nor undefined
>
Can we have an isnull() function then, please. Otherwise there's no
operation to test for nullness.
PS: Nullness? Nullility?
