On Fri, Jun 5, 2026 at 10:08 PM Tom Lane <[email protected]> wrote: > > Heikki Linnakangas <[email protected]> writes: > > On 5 June 2026 10:48:00 EEST, Chao Li <[email protected]> wrote: > >> evantest=# create domain d_div as int check (1 / (value - 1) > 0); > >> CREATE DOMAIN > >> evantest=# create table t (a int); > >> CREATE TABLE > >> evantest=# alter table t add column b d_div default 1; > >> ERROR: division by zero > > > It seems totally reasonable to get an error in that case. '1' is not a > > valid value for the datatype, whether or not there are any rows in the > > table. > > I think there's reason for concern here, which is that we do not throw > an error for the apparently equivalent case > > regression=# create table t2 (a int, b d_div default 1); > CREATE TABLE > > This will give you an error at INSERT, but not CREATE. So this > is inconsistent, as well as different from the pre-v19 behavior. >
However, this is normal behavior for non-domain types. create table t2 (a numeric default (1::numeric/0.0::float4)); -- ok alter table t2 add column b numeric default ((1::numeric/0.0::float4)); -- error
