本次實驗測試，oracle數據庫視圖中v$,v_$,gv$之間的關系
總結：
v_$是動態性能視圖，通過sql查詢數據庫基表返回記錄。例如，v_$database對象是視圖類型，可對其它用戶授權訪問；
v$database則是為了簡化查詢，是v_$database的同義詞，oracle同義詞無法作為對象，進行賦權語句執行grant；
gv_則是集群，多了一個Inst_id區分實例
1.對象類型
1 SYS@ceshi>select object_name,object_type,status from user_objects where object_name in('V$SESSION', 2 11:02:55 2 'V_$SESSION','GV$SESSION'); 3 4 OBJECT_NAME OBJECT_TYPE STATUS 5 ------------------------------ ------------------- ------- 6 V_$SESSION VIEW VALID 7 8 SYS@ceshi>select synonym_name,table_name from dba_synonyms where synonym_name in('V$SESSION','GV$SESSION'); 9 10 SYNONYM_NAME TABLE_NAME 11 ------------------------------ ------------------------------ 12 GV$SESSION GV_$SESSION 13 V$SESSION V_$SESSION
2.授權報錯
1 11:08:46 SYS@ceshi>grant select on V_$SESSION to scott; 2 3 Grant succeeded. 4 5 Elapsed: 00:00:00.13 6 11:09:19 SYS@ceshi>grant select on V$SESSION to scott; 7 grant select on V$SESSION to scott 8 * 9 ERROR at line 1: 10 ORA-02030: can only select from fixed tables/views
授權，需要授予對象權限，同義詞無法作為授權對象
3.GET_DDL
提取GV$SESSION基表定義，如下鏈接可以幫助查詢，普通get_ddl查詢的定義是錯誤的
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