CREATE OR REPLACE FUNCTION notify_albums_change() RETURNS trigger AS $trigger$
DECLARE
  rec albums;
  dat albums;
  payload TEXT;
BEGIN

  -- Set record row depending on operation
  CASE TG_OP
  WHEN 'UPDATE' THEN
     rec := NEW;
     dat := OLD;
  WHEN 'INSERT' THEN
     rec := NEW;
  WHEN 'DELETE' THEN
     rec := OLD;
  ELSE
     RAISE EXCEPTION 'Unknown TG_OP: "%". Should not occur!', TG_OP;
  END CASE;

  -- Build the payload
  payload := json_build_object('timestamp',CURRENT_TIMESTAMP,'action',LOWER(TG_OP),'db_schema',TG_TABLE_SCHEMA,'table',TG_TABLE_NAME,'record',row_to_json(rec), 'old',row_to_json(dat));

  -- Notify the channel
  PERFORM pg_notify('albums', payload);

  RETURN rec;
END;
$trigger$ LANGUAGE plpgsql;

CREATE TRIGGER albums_notify AFTER INSERT OR UPDATE OR DELETE 
ON albums
FOR EACH ROW EXECUTE PROCEDURE notify_albums_change();