Am 24.03.24 um 16:28 schrieb Thiemo Kellner:
>
> Am 24.03.2024 um 16:17 schrieb Tom Lane:
>
>> To do that, we'd have to remember that you'd said NULL, which we
>> don't: the word is just discarded as a noise clause. Considering
>> that this usage of NULL isn't even permitted by the SQL standard,
>> that seems like a bit too much work.
>
> If I understood correctly, only the NOT NULL expression gets
> remembered, but the NULL gets discarded. No, I do not quite get it.
> Somehow, it has to be decided whether to create a "check constraint"
> or not, but this information is not available any more when creating
> the primary key? Not even in some kind of intermediary catalogue?
the null-able constraint addition to a column is pointless because by
default all columns are nullable. definition as a primary key adds the
not null constraint.
Andreas
--
Andreas Kretschmer
CYBERTEC PostgreSQL Services and Support