Thread

Re: BUG #19351: in pg18.1,when not null exists in the table , and add constraint problem.

Srinath Reddy Sadipiralla <srinath2133@gmail.com> — 2025-12-10T16:40:02Z

On Wed, Dec 10, 2025 at 9:32 PM Srinath Reddy Sadipiralla <
srinath2133@gmail.com> wrote:

> why it's not treated as normal
> constraint and why we are not throwing an error
> like the constraint already exists?
>

ah... just after a quick code lookup, remembered that
"not null" is treated as a column property, which is a
flag in pg_attribute catalog table named as "attnotnull",
i guess the reason(s) it's a column property rather than
constraint might be an overkill, adds overhead of entries
in pg_constraint, or historical reasons, please correct me
if i am wrong, still the right way of setting this constraint "ALTER TABLE
test_null_20251210 ALTER COLUMN c1 SET NOT NULL;"
not throwing an error; i think it makes sense to throw an
error here, thoughts?

-- 
Thanks,
Srinath Reddy Sadipiralla
EDB: https://www.enterprisedb.com/