Re: ALTER DOMAIN ADD NOT NULL NOT VALID

On Thu, Aug 14, 2025 at 5:02 PM Kirill Reshke <reshkekirill(at)gmail(dot)com> wrote:
>
> I have few observations.
> One is whether we should now support CREATE DOMAIN ... NOT NULL NOT
> VALID syntax? This could be a separate patch though.
>

in gram.y:

CreateDomainStmt:
CREATE DOMAIN_P any_name opt_as Typename ColQualList
{
CreateDomainStmt *n = makeNode(CreateDomainStmt);

n->domainname = $3;
n->typeName = $5;
SplitColQualList($6, &n->constraints, &n->collClause,
yyscanner);
$$ = (Node *) n;
}
;

ColConstraintElem:
NOT NULL_P opt_no_inherit
{
Constraint *n = makeNode(Constraint);
n->contype = CONSTR_NOTNULL;
n->location = @1;
n->is_no_inherit = $3;
n->is_enforced = true;
n->skip_validation = false;
n->initially_valid = true;
$$ = (Node *) n;
}
| NULL_P
{
Constraint *n = makeNode(Constraint);

n->contype = CONSTR_NULL;
n->location = @1;
$$ = (Node *) n;
}

CREATE DOMAIN use ColConstraintElem.
that's why we do not support syntax:
``create domain t1 as int not null not valid;``

we also do not support column constraints NOT NULL NOT VALID.
Like
``create table t(a int not null not valid);``
will error out.
so I guess it's fine to not support it?

opt_not_valid: NOT VALID { $$ = true; }
| /* EMPTY */ { $$
= false; }
;
ColConstraintElem:
NOT NULL_P opt_no_inherit opt_not_valid
{
Constraint *n = makeNode(Constraint);

n->contype = CONSTR_NOTNULL;
n->location = @1;
n->is_no_inherit = $3;
n->is_enforced = true;
// n->skip_validation = false;
// n->initially_valid = true;
n->skip_validation = $4;

n->initially_valid = !n->skip_validation;

$$ = (Node *) n;
}

the above change will produce error
/usr/bin/bison -Wno-deprecated -o src/backend/parser/gram.c -d
../../Desktop/pg_src/src9/postgres/src/backend/parser/gram.y
../../Desktop/pg_src/src9/postgres/src/backend/parser/gram.y: error:
shift/reduce conflicts: 1 found, 0 expected
../../Desktop/pg_src/src9/postgres/src/backend/parser/gram.y: note:
rerun with option '-Wcounterexamples' to generate conflict
counterexamples

so currently I don't know how to support syntax
``create domain t1 as int not null not valid;``

I also found it's hard to psql-tab-complete for
'alter domain ... add constraint .. not null' with 'not valid'.