text: BEGIN;
  
  ALTER TABLE
      poster
  ADD
      COLUMN access_log boolean,
  ADD
      COLUMN author_online_only boolean;
  
  UPDATE
      poster
  SET
      access_log = false,
      author_online_only = false;
  
  ALTER TABLE
      poster
  ALTER COLUMN
      access_log
  SET
      NOT NULL,
  ALTER COLUMN
      author_online_only
  SET
      NOT NULL;
  
  ALTER TABLE
      poster_viewer
  ADD
      COLUMN access_log boolean;
  
  UPDATE
      poster_viewer
  SET
      access_log = false;
  
  ALTER TABLE
      poster
  ALTER COLUMN
      access_log
  SET
      NOT NULL;
  
  COMMIT;