oracle11g中默认设置了 “FAILED_LOGIN_ATTEMPTS=10次”，当输入密码错误次数达到设置值将导致此，该用户会自动锁住。
1. conn sys/oracle as sysdba
2. select username,account_status from dba_users where username='MBI';，查看到用户锁了
3. 解锁xxx用户，SQL> alter user MBI account unlock;
4. 查看用户限制登陆次数select * from dba_profiles where RESOURCE_NAME='FAILED_LOGIN_ATTEMPTS';
5. alter profile default limit failed_login_attempts unlimited;修改用户无论输入多少次都不会被锁定