At 06:03 PM 10/4/2004, Geoff Worboys wrote:

> > create un_table (c1 int unique)
> > <insert rows>
> > update un_table set c1 = c1 + 1
> > is valid.
>
>Valid maybe, but it only works in certain situations, not
>reliably.

According to the standard, the constraint is consistent with
the update and should work reliably. Firebird checks its
constraints before the "operation". The standard says that
immediate constraints are checked after the "verb". The
verb is the whole of the update, not the change to individual
records.


Regards,

Ann