【摘要】 数据库数据组织的无环性是数据库理论和应用中一个重要特性 如何把数据库模式分解成无环性是一个比较复杂的问题 ,特别是在FD集F有内部冲突时无α环的分解问题 为了解决这一问题 ,讨论了有内部冲突的FD集F有广义左部冲突或广义右部冲突时和对称左部属性集之间的关系 ,以及对称左部属性集存在的条件和性质 ;给出了相关概念、定理及证明 在此基础上 ,给出了关于存在广义左部、右部冲突的判定算法 ,对该算法进行了正确性证明和算法分析更多还原

【Abstract】 The acyclic property of database data structure is an important property of the database theory and application. How to make an acyclic decomposition of the database schema is a relatively complex problem, and more complex is the α-acyclic decomposition problem when there exist inside conflicts in FD set F. Discussed in this paper is that when there exist generalized left-hand side conflicts or generalized right-hand side conflicts in FD set F which has inside conflicts, the relationship between the generalized left-hand side or generalized right-hand side conflicts and the symmetrical left-hand side attribute set, and the existing condition and property of the symmetrical left-hand side attribute set. The corresponding concepts, theorems and proof are also given. On this basis, a decision algorithm of the existence of generalized left-hand side or generalized right-hand side conflicts is presented. The correctness verification and algorithm analysis of the above mentioned algorithm are presented too.更多还原