Chinese variable question marks in Oracle data tables

Check the Select Userenv (' language ') from dual first, view the Oracle character set,

$ sqlplus/nolog

Sql> Connect sys/oracle as Sysdba

Sql> Startup

How to set the encoding for an Oracle database (ZHS16GBK) modified to UTF8

sql> shutdown immediate;

sql> startup Mount;

Sql> alter system enable restricted session;

Sql> alter system set job_queue_processes=0;

sql> ALTER DATABASE open;

Sql> ALTER DATABASE character set Internal_use UTF8;

sql> shutdown immediate;

Sql> startup;

Chinese variable question marks in Oracle data tables