Re: Check constraint failure messages

CREATE OR REPLACE FUNCTION po.confirm(p_val anyelement, p_validated boolean)
RETURNS boolean LANGUAGE plpgsql STRICT IMMUTABLE PARALLEL SAFE AS $$
BEGIN
  IF NOT p_validated THEN
    RAISE WARNING 'Invalid value: %', p_val;
  END IF;
  RETURN p_validated;
END;
$$;
COMMENT ON FUNCTION po.confirm(anyelement,boolean) IS
'Raises a warning when a condition is false; useful for outputting CHECK constraint error values.';

CREATE DOMAIN po.email AS varchar

  CHECK (po.confirm(VALUE, VALUE IS NULL OR NOT po.email_expanded(VALUE) IS NULL));