A.確保數(shù)據(jù)的精確性 B.定義和儲(chǔ)存數(shù)據(jù)對(duì)象 C.幫助查看數(shù)據(jù) D.儲(chǔ)存數(shù)據(jù)
A.USER_VIEWS B.USER_TABLES C.ALL_OBJECTS D.USER_OBJECTS