(1)數(shù)據(jù)項(xiàng); (2)數(shù)據(jù)結(jié)構(gòu); (3)數(shù)據(jù)流; (4)數(shù)據(jù)存儲(chǔ); (5)處理邏輯; (6)外部實(shí)體。