At 06:56 PM 24/02/2006, you wrote:

> >
> > WHY is your application code performing dynamic DDL at all?
> > Because sometimes we require to show some computation on some reports
> > to a lot of client and this was the simplest and quickest way without
> > involving other application layer.
> >

It sounds even more wrong to be altering the table from your
app. There are two better (safer, quicker, testable) ways to do this
sort of thing.

1) Defined the computed fields permanently (they'll never be
calculated unless you include them in SELECT statements)
or 2) (better)
2) create views containing the computed fields you want for reports, etc.

./heLen