Selection of the character set for Oracle 10g installation, and the modification behind it

First log in to Sqlplus with system and password, and then:

1. Log in to Oracle with SYS
Connect sys/password as SYSDBA; (Can I log in to sqlplus directly with SYS?) ）
2. Start to modify the code
Shutdown immediate; Stop Oracle services and listen. If the service is stopped, this can be omitted
startup Mount;
Alter system enable restricted session;
alter system set job_queue_processes=0; Initialize Setup job
ALTER DATABASE open;
ALTER DATABASE character set Internal_use UTF8; set encoding
Shutdown immediate;
Startup
The encoding is now set to complete.

Selection of the character set for Oracle 10g installation, and the modification behind it