--使用SYS.USER$.PASSWORD恢复的历史密码不区分大小写， --使用SYS.USER$.PARE4恢复的历史密码却严格区分大小写， SQL> select password,spare4 from user$ where name = 'EASDBA'; PASSWORD -------------------------------------------------------------------------------- SPARE4 -------------------------------------------------------------------------------- 20C3BA8582A406D9 S:CBC48054705839F2B2A09EEF70D4A6700F3415E10D54CA8BD90C09EA8FC1 SQL> alter user EASDBA identified by values '20C3BA8582A406D9'; User altered. SQL> select password,spare4 from user$ where name = 'EASDBA'; PASSWORD -------------------------------------------------------------------------------- SPARE4 -------------------------------------------------------------------------------- 20C3BA8582A406D9