I would preffer using meaningfull function names that make sense when
reading it. I like the idea of an Updated() or even Modified()
function call. Its stright to the point.

With regards to to null's i think the definition is begin confused
with regards to the inital post. With updated we don't want to know:

"is the old the value different to the new one, but if null then maybe
handle it differently"

we want to know "did the value change". Hence if the new value is in
no way the same as the old, be it null or not, it was Updated. If in a
particular trigger you need to handle or work with nulls differently
then thats up to you as a developer.

Giulio

--- In Firebird-Architect@yahoogroups.com, "Samofatov, Nickolay"
<nickolay@b...> wrote:

> Hi, Dmitri!
>
> > Thursday, September 9, 2004, 6:36:28 PM, you wrote:
> >
> > ABS> If (
> > ABS> (Old.Quantity <> New.Quantity) or
> > ABS> ((Old.Quantity is null) and (New.Quantity is not null)) or
> > ABS> ((Old.Quantity is not null) and (New.Quantity is null))
> > ABS> ) then
> >
> > Yaffil supports MS SQL-style == operator, i.e. yours code can
> > be changed to
> >
> > if (Old.Quantity !== New.Quantity) then
> >
> > if I've not have mistaken.
> >
> > But, this is the question - will be == migrated from Yaffil
> > to Firebird as other Yaffil features.
>
> Last time I was talking to Dmitry Emanov he told me this Yaffil piece is
> still a little bit flacky to be ported into Firebird safely at the
> moment.
>
> My opinion is that we should not go PostgreSQL way introducing 50+
> custom operators made of all combinations of =, *, ~, ^, /, |, !, -, ?,
> #, &, <, >, @ etc.
>
> Oracle way of adding built-in functions seems like better idea to me.
> Something like MODIFIED(A, B) returning TRUE if A differs from B
> considering null as a special value seems to look better.
> People can better read words instead of remembering 50 non-standard
> symbol combinations. Note that many people come from C/C++ background
> and may start mismatching = and == in expressions by accident. C/C++
> would give a warning in such cases while Firebird won't.
>
> > Dmitri Kouzmenko
>
> Nickolay