三元關係中隱含二元關係之無效的最小基數限制

On Invalid Minimum Cardinality Constraints of the Implicit Binary Relationships in the Ternary Relationship

李佳璇(Jia-Shiuan Lee) ； 黃其彥(Chi-Yen Huang)

《臺北科技大學學報》 42卷1期 (2009/06) Pp. 51-66

https://doi.org/10.29768/JNTUT.200906.0004

摘要

三元關係(Ternary relationship)被廣泛的使用於實體關聯模型化中，一個三元關係常常可以被分解成多個參與之實體所組成之二元關係(Binary relationship)，此時，這些二元關係是否存在衝突攸關實體關聯模型之有效性。先前之研究在探討此一問題時，大多以最大基數(Maximum cardinality)為分析基礎，本文嘗試以最小基數(Minimum cardinality)切入此問題，探討這些二元關係之有效性，經由本文提出之法則，可辨識出很多最小基數無效之限制關係。

關鍵字

三元關係 ； 基數限制 ； 結構有效性 ； 實體關聯模型

並列摘要

The ternary relationship is widely used in entity-relationship modeling. A ternary relationship can be decomposed into many binary relationship semantics between the entities. Therefore, the state of these binary relationships is highly related to the validity of the model. Unlike other analyses using only maximum cardinality constraints, the paper adopted minimum cardinality constraints to evaluate the structural validity of the binary relationships in the ternary relationship. Based on the rule proposed, many invalid structures in the ternary relationship can be identified clearly.

並列關鍵字

ternary relationship ； cardinality constraints ； structural validity ； entity-relationship model