text: BEGIN;
  
  -- acts as a substitute for the agent_version column. If the crawler knows the ID of the found agent version
  -- it can already provide it here. This means less work for the database.
  ALTER TABLE raw_visits
      ADD COLUMN agent_version_id INT;
  
  -- acts as a substitute for the protocols column. If the crawler knows the IDs of the found protocols
  -- it can already provide it here. It's also possible to partially fill both columns.
  ALTER TABLE raw_visits
      ADD COLUMN protocol_ids INT[];
  
  COMMIT;
  