anchor.diff:      ;
   
   supplemental_db_logging
  -    : (ADD | DROP) SUPPLEMENTAL LOG (DATA
  -                                    | supplemental_id_key_clause
  -                                    | supplemental_plsql_clause
  -                                    )
  -    ;
  -
  +    :  add_or_drop
  +          SUPPLEMENTAL LOG (DATA
  +                           | supplemental_id_key_clause
  +                           | supplemental_plsql_clause
  +                           )
  +    ;
  +
  +add_or_drop
  +    : ADD
  +    | DROP
  +    ;
   
   supplemental_plsql_clause
       : DATA FOR PROCEDURAL REPLICATION
  
positive.code: 
  alter_datafile_clause
      : DATAFILE (','? filename|filenumber)+ 
          (ONLINE
          | OFFLINE (FOR DROP)?
          | RESIZE size_clause
          | autoextend_clause
  
negative.code: 
  startup_clauses
      : MOUNT ((STANDBY | CLONE) DATABASE)?
      | OPEN (READ WRITE)? resetlogs_or_noresetlogs? upgrade_or_downgrade?
      | OPEN READ ONLY
      ;
  
  resetlogs_or_noresetlogs
      : RESETLOGS
      | NORESETLOGS
      ;
     
  upgrade_or_downgrade
      : UPGRADE
      | DOWNGRADE
      ;
   
  recovery_clauses
      : general_recovery
      | managed_standby_recovery
      | begin_or_end BACKUP
      ;
  
  begin_or_end
      : BEGIN
      | END
      ;
  
  general_recovery
  