怎样修改数据库的character ？急！

修改PROPS$表，但是Oracle好像不推荐这样

SVRMGR>; select * from props$;
NAME                         VALUE$                                                                         COMMENT$
------------------------------ -------------------------------------------------------------------------------- --------------------------------------------------------------------------------
DICT.BASE                   2                                                                               dictionary base tables version #
DBTIMEZONE                   0:00                                                                            DB time zone
NLS_LANGUAGE                AMERICAN                                                                      Language
NLS_TERRITORY                AMERICA                                                                         Territory
NLS_CURRENCY                $                                                                               Local currency
NLS_ISO_CURRENCY             AMERICA                                                                         ISO currency
NLS_NUMERIC_CHARACTERS       .,                                                                            Numeric characters
NLS_CHARACTERSET             ZHS16GBK                                                                      Character set
NLS_CALENDAR                GREGORIAN                                                                      Calendar system
NLS_DATE_FORMAT             DD-MON-RR                                                                      Date format
NLS_DATE_LANGUAGE             AMERICAN                                                                      Date language
NLS_SORT                      BINARY                                                                         Linguistic definition
NLS_TIME_FORMAT             HH.MI.SSXFF AM                                                                Time format
NLS_TIMESTAMP_FORMAT          DD-MON-RR HH.MI.SSXFF AM                                                       Time stamp format
NLS_TIME_TZ_FORMAT          HH.MI.SSXFF AM TZH:TZM                                                          Time with timezone format
NLS_TIMESTAMP_TZ_FORMAT       DD-MON-RR HH.MI.SSXFF AM TZH:TZM                                              Timestamp with timezone format
NLS_DUAL_CURRENCY             $                                                                               Dual currency symbol
NLS_COMP                      BINARY                                                                         NLS comparison
NLS_NCHAR_CHARACTERSET       ZHS16GBK                                                                      NCHAR Character set
NLS_RDBMS_VERSION             8.1.7.0.0                                                                      RDBMS version for NLS parameters
GLOBAL_DB_NAME                OTADB.MBOX.MONTERNET.COM                                                       Global database name
EXPORT_VIEWS_VERSION          8                                                                               Export views revision #