Oracle和plsqldeveloper编码设置
  在使⽤pl/sql developer时，查询出来中⽂字段显⽰乱码，因为数据库的编号格式和pl /sql developer的编码格式不统⼀造成的。⼀、查看和修改oracle数据库字符集
plsql developer导入数据select userenv('language') from dual;
--查询结果：
SIMPLIFIED CHINESE_CHINA.AL32UTF8
--修改oracle数据库字符集：（在SQL Plus中）
sql> conn / as sysdba;
sql> shutdown immediate;
database closed.
database dismounted.
oracle instance shut down.
sql> startup mount;
oracle instance started.
total system global area 135337420 bytes
fixed size 452044 bytes
variable size 109051904 bytes
database buffers 25165824 bytes
redo buffers 667648 bytes
database mounted.
sql> alter system enable restricted session;
system altered.
sql> alter system set job_queue_processes=0;
system altered.
sql> alter system set aq_tm_processes=0;
system altered.
sql> alter database open;
database altered.
sql> alter database character set internal_use JA16SJIS;
sql> shutdown immediate;
sql> startup;
⼆、修改pl/sql developer 的编码
  在windows中创建⼀个名为“NLS_LANG”的系统环境变量，设置其值为“SIMPLIFIED CHINESE_CHINA.ZHS16GBK”，然后重新启动pl/sql developer，这样检索出来的中⽂内容就不会是乱码了。如果想转换为UTF8字符集，可以赋予“NLS_LANG”为
“AMERICAN_AMERICA.UTF8”，然后重新启动 pl/sql developer。其它字符集设置同上