Bc. Jiri Cincura escreveu:

>Hi,
>
>today morning I was thinking about the Boolean simulation in FB 1.5 . I've
>found two solutions.
>1: char(1) with 'T' and 'F' and some validation (check, trigger)
>2: char(1) with X (as Yes/True) and NULL (No/False)
>
>What's better (performance, management, ...)?
>How you're working with Boolean?
>
>
>

The first one. NULL is a non-value and can't be compared to
anything. A NULL in a expression always results NULL, no
mather which expression (except when using COALESCE,
of course).

Ivan.