alter_command

alter_command 
      ::= alter_cluster 
      | alter_database 
      | alter_index 
      | alter_profile 
      | alter_cost 
      | alter_role 
      | alter_rollback 
      | alter_sequence 
      | alter_session 
      | alter_snapshot 
      | alter_snapshot_log 
      | alter_system 
      | alter_table 
      | alter_tablespace 
      | alter_trigger 
      | alter_user 
      | alter_view 

[rule list]
This rule is call by

to_define_data