摘要： 无环分解是数据库数据组织的一个重要环节,在实际数据库设计中具有重要意义。为了深入研究它,该文分析了在FD集F的最小归并依赖集D存在弱左部或弱右部冲突时所具有的性质和特征。在此基础上讨论了它的模式分解问题,给出了在D有弱冲突时满足无损连接、保FD、BCNF的分解是有α环的结论,为进一步研究无α环的分解奠定了基础。

关键词: 无内部冲突, 弱冲突, α环, 最小归并依赖集, 模式分解

Abstract: Acyclic decomposition is an important aspect of the database data structure. It has important meaning in actual database design. To study it deeply, this paper analyzes the property and characteristics when there exist weak left-hand side or weak right-hand side conflicts in the minimal merge dependency set D of FD set F. On this basis, it discusses its scheme decomposition and concludes that when D has weak conflict, the decomposition meeting join-lossless, FD and BCNF is α-cyclic, laying the foundation for further investigation of α-acyclic decomposition.

中图分类号: 

• TP311