重建Oracle 10g EM

１.执行emca -reconfig dbcontrol db -repos recreate

２.如果执行失败，需用sys帐号登录到oracle,执行以下语句：

    drop user sysman cascade;
    drop role MGMT_USER;
    drop user MGMT_VIEW cascade;

    drop public synonym MGMT_TARGET_BLACKOUTS;
    drop public synonym SETEMVIEWUSERCONTEXT;