Re: Trouble referencing a multi-column unique constraint by name in ON CONFLICT clause

Charles Leifer <coleifer@gmail.com> writes:
> I'm running into behavior I don't understand when trying to do an UPSERT
> with Postgres. The docs would seem to indicate that the conflict target of
> the INSERT statement can be either an index expression or a constraint
> name. However, when attempting to reference the constraint name, I get a
> "column ... does not exist" error.

What I see in the INSERT reference page is

    where conflict_target can be one of:

    ( { index_column_name | ( index_expression ) } [ COLLATE collation ] [ opclass ] [, ...] ) [ WHERE index_predicate
]
    ON CONSTRAINT constraint_name

So you can write a parenthesized list of column names, or you can write
"ON CONSTRAINT constraint_name".  Given your second example with

create table kv (
  key text,
  value text,
  extra text,
  constraint kv_key_value unique(key, value));

either of these work for me:

regression=# insert into kv (key, value, extra) values ('k1', 'v1', 'e1')
  on conflict (key, value) do update set extra=excluded.extra;
INSERT 0 1
regression=# insert into kv (key, value, extra) values ('k1', 'v1', 'e1')
  on conflict on constraint kv_key_value do update set extra=excluded.extra;
INSERT 0 1

            regards, tom lane