In VAX DBMS, the data items defined in a record whose contents are used by DBCS (Database Control System) to calculate a database key value when a record occurrence is stored.; 在VAX DBMS中,記錄中的數(shù)據(jù)項(xiàng)。當(dāng)數(shù)據(jù)庫(kù)中存有具體值時(shí),數(shù)據(jù)庫(kù)控制系統(tǒng)用該數(shù)據(jù)項(xiàng) 中的內(nèi)容去計(jì)算數(shù)據(jù)庫(kù)鍵值。