For sa & d projects , all foreign keys are identified and marked in the entity description part iii ( entity key description ) . for sa & d projects , all entities are in third normal form ( 3nf ) 對于系統(tǒng)分析及設計的計劃,所有外鍵碼須經(jīng)認定,并且在數(shù)據(jù)實體描述的第iii部分(數(shù)據(jù)實體關鍵碼描述)界定。
百科解釋
In computer science, the third normal form (3NF) is a normal form used in database normalization. 3NF was originally defined by E.