===== DB LINK 생성 =====
<code sql>
create public database link DBLINK_PRD
connect to ADMIN
identified by "******"
using '(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=ais-rds-prd.ciram51bv0wk.ap-northeast-2.rds.amazonaws.com)(PORT=51521))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=ASICSDB)))';
</code>
===== DB Object Gap 분석 =====
<code sql>
SELECT owner
      ,object_type
      ,object_name 
      ,MAX(DEV_STS) DEV_STS
      ,MAX(PRD_STS) PRD_STS

FROM (
      SELECT owner
            ,object_type
            ,object_name 
            ,status DEV_STS
            ,NULL PRD_STS
      FROM dba_objects a
      WHERE owner IN ('AALIB','COMLIB','AHLIB','ASLIB')
      UNION ALL
      SELECT owner
            ,object_type
            ,object_name 
            ,NULL DEV_STS
            ,STATUS PRD_STS
      FROM dba_objects@DBLINK_PRD a
      WHERE owner IN ('AALIB','COMLIB','AHLIB','ASLIB')
     )
GROUP BY owner
        ,object_type
        ,object_name 
HAVING nvl(MAX(DEV_STS),'NULL') <> NVL(MAX(PRD_STS),'NULL')
ORDER BY owner
        ,object_type
        ,object_name 
; 
</code>
==== DB link 사용예 ====
-- Production DB의 COMLIB.APP_USER 테이블 조회하기
<code sql>
SELECT *
FROM COMLIB.APP_USER@DBLINK_PRD;
</code>