oracle18c在Linux下PDB库默认字符集调整

主要是原来的是gbk的，放到utf8下面，各种长度不够

以下是调整过程：

//查看Pdb
show pdbs;
//删除pdb
drop pluggable database testpdb including datafiles;
//创建pdb
create pluggable database testpdb admin user testpdb identified by testpdb file_name_convert=('/opt/oracle/oradata/ORCLCDB/pdbseed/','/oracle/oradata/testpdb/');
//打开数据库
alter pluggable database testpdb open;
//确认字符集
alter session set container=testpdb;
select userenv('language') from dual;
//修改字符集
alter pluggable database testpdb close immediate instances=all;
alter pluggable database testpdb open read write restricted;
alter database character set internal_use zhs16gbk;
alter pluggable database testpdb close immediate;

--启动pdb确认
alter pluggable database testpdb open instances=all;
alter session set container=testpdb;
select userenv('language') from dual;  <<<<<<<<<<此时字符集已经修改

//切换到cdb
alter session set container=CDB$ROOT;
alter pluggable database all save state;