你是从哪里百度来的,你要看一下官方文档,分别看一下9i、10g、11g关于此参数的说法
9i的时候确实如你所说:
SHARED
More than one database can use a password file. However, the only user recognized by the password file is SYS.
10g以后:
shared
One or more databases can use the password file. The password file can contain SYS as well as non-SYS users.
另外,10g中的官档也有些小错误,说 exclusive与shared有相同的行为,这是错误的,再11g这个错误修正了。