首先通过sqlplus连接数据库，将正在运行的数据库实例关掉（例如将数据库编码改为utf-8）

具体操作如下：

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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