–alter system set audit_syslog_level=’DB, EXTENDED’ scope=spfile sid=’*’;
alter system set audit_trail=DB, EXTENDED scope=spfile sid=’*’;

ALTER SYSTEM SET audit_sys_operations=TRUE
COMMENT=’Begin auditing SYS’
SCOPE=spfile SID=’*’;

ALTER SYSTEM SET audit_trail=xml,extended
COMMENT=’enables database auditing and prints all columns of the audit trail, including SqlText and SqlBind values’
SCOPE=spfile SID=’*’;

alter system reset audit_syslog_level scope=spfile sid=’*’;

alter system set audit_syslog_level=” scope=spfile sid=’*’;
alter system set audit_trail=’NONE’ scope=spfile sid=’*’;