On Mon, 24 Jul 2023 at 17:42, Alvaro Herrera <alvhe...@alvh.no-ip.org> wrote: > > On 2023-Jul-24, Dean Rasheed wrote: > > > Something else I noticed: the error message from ALTER TABLE ... ADD > > CONSTRAINT in the case of a duplicate constraint name is not very > > friendly: > > > > ERROR: duplicate key value violates unique constraint > > "pg_constraint_conrelid_contypid_conname_index" > > DETAIL: Key (conrelid, contypid, conname)=(16540, 0, nn) already exists. > >
To reproduce this error, try to create 2 constraints with the same name on different columns: create table foo(a int, b int); alter table foo add constraint nn not null a; alter table foo add constraint nn not null b; I found another, separate issue: create table p1(a int not null); create table p2(a int); create table foo () inherits (p1,p2); alter table p2 add not null a; ERROR: column "a" of table "foo" is already NOT NULL whereas doing "alter table p2 alter column a set not null" works OK, merging the constraints as expected. Regards, Dean
