已选择6行。

关于密码版本的问题：

SELECT USERNAME,PASSWORD_VERSIONS FROM DBA_USERS;

USERNAME PASSWORD_VERSIONS

------------------------------ -----------------

JONES 10G 11G

ADAMS 10G 11G

CLARK 10G 11G

PRESTON 11G

BLAKE 10G

The passwords for accounts jones, adams, and clark were originally created in Release 10gand then reset in Release 11g. Their passwords, assuming case sensitivity has been enabled, are now case sensitive, as is the password for preston. However, the account for blake is still using the Release 10gstandard, so it is case insensitive. Ask him to reset his password so that it will be case sensitive, and therefore more secure.

关于限制SYS用户的密码严格区分大小写：

orapwd file=orapw entries=100 ignorecase=n

Enter password for SYS: password

This creates a password file called orapwd. Because ignorecase is set to n (no), the password entered for the password parameter will be case sensitive. Afterwards, if you connect using this password, it succeeds—as long as you enter it using theexactcase sensitivity in which it was created. If you enter the same password but withdifferentcase sensitivity, it will fail.

If you set ignorecase to y, then the passwords in the password file are case insensitive, which means that you can enter the password using any capitalization that you want.

If you imported user accounts from a previous release and these accounts were created with SYSDBA or SYSOPER privileges, then they will be included in the password file. The passwords for these accounts are case insensitive. The next time these users change their passwords, and assuming case sensitivity is enabled, the passwords become case sensitive. For greater security, have these users change their passwords.

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