Postgres 14

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CREATE TABLE IF NOT EXISTS myval
(
    id integer GENERATED ALWAYS AS IDENTITY,
    name character varying(255),
    CONSTRAINT "PK_aa671c3359a0359082a84ecb801" PRIMARY KEY (id)
);

CREATE TABLE

-- This will work
INSERT INTO myval (name) VALUES ('foo');

INSERT 0 1

--  This will fail
INSERT INTO myval (id,name) VALUES (2,'bar');

ERROR:  cannot insert a non-DEFAULT value into column "id"
DETAIL:  Column "id" is an identity column defined as GENERATED ALWAYS.
HINT:  Use OVERRIDING SYSTEM VALUE to override.

SELECT * FROM myval;

id
name

1
foo

SELECT 1

-- This disable the GENERATED ALWAYS AS IDENTITY constraint for the insert statement
INSERT INTO myval (id,name) OVERRIDING SYSTEM VALUE
VALUES (42,'bar'); 

INSERT 0 1

SELECT * FROM myval;

id
name

1
foo

42
bar

SELECT 2