FD环境下满足P_S及无α环模式分解问题研究

Research of Schema Decomposition Problem into Meeting P_S and Without α-cycle in Functional Dependency

通过分析在FD集F的最小归并依赖集存在弱左部或弱右部冲突时所具有的性质和特征,讨论并给出了满足PS(保持FD,无损连接且满足SNF)且无α环分解的充要条件和算法,对算法的正确性、可终止性进行了证明,并对算法的时间复杂度给出了分析。

By analyzing the property and characteristics of the minimum merge dependency set of F when D has weak left side conflict or weak right side conflict, the necessary and sufficient condition under which a database schema without inside conflict can be decomposed into one meeting Ps and α-acyclic is given. A decomposition algorithm is given accordingly with the proof for its termination and correction.