建立trigger:

CREATEORREPLACETRIGGERlogon_denied_write_alertlogAFTERSERVERERRORONDATABASEDECLAREl_messagevarchar2(2000);BEGIN--ORA-1017:invalidusername/password;logondeniedIF(IS_SERVERERROR(1017))THENselect'Failedloginattempttothe"'||sys_context('USERENV','AUTHENTICATED_IDENTITY')||'"schema'||'using'||sys_context('USERENV','AUTHENTICATION_TYPE')||'authentication'||'at'||to_char(logon_time,'dd-MON-yyhh34:mi:ss')||'from'||osuser||'@'||machine||'['||nvl(sys_context('USERENV','IP_ADDRESS'),'UnknownIP')||']'||'viathe"'||program||'"program.'intol_messagefromsys.v_$sessionwheresid=to_number(substr(dbms_session.unique_session_id,1,4),'xxxx')andserial#=to_number(substr(dbms_session.unique_session_id,5,4),'xxxx');--writetoalertlogsys.dbms_system.ksdwrt(2,l_message);ENDIF;END;