XML与关系数据集成中的数据同步修改技术

XML与RDB的同步修改是基于RDB的XML管理技术中实现XML视图与底层RDB数据一致性的根本保障，有关XML修改及其与RDB集成后的同步修改技术的研究尚未系统开展。文中提出了一种XML修改语言原型FLWU(FOR、LET、WHERE、UPDATE)；通过FLWU到SQL的转换及两者之间同步执行机制的建立，实现XML与RDB的同步修改，从而保证基于RDB的XML数据管理中XML视图与底层RDB的数据一致性。

Synchronized Update in Data Integration between XML and RDB

Synchronized update between XML (Extensible Markup Language) and RDB (Relational Database) is the basis for ensuring data consistency between XML view and bottom RDB in RDB-based XML management technology. Up to now, the update on XML as well as the synchronized update on integrated data between XML and RDB has not been studied systematically mainly because existing methods all focus on document update of XML and neglect the full update process. We propose extending XQuery, the standard XML query language recommended by W3C, through making its function include both query and update. XQuery includes the three rule sentences FOR, LET, WHERE; naturally, as our proposed extension adds UPDATE, we call our proposed protocol of XML Update Language FLWU. The UPDATE sentence consists of eleven update operations on not only XML contents but also XML structure. Then FLWU is decomposed into FLWI (FOR,LET,WHERE,INSERT) and FLWD(FOR,LET,WHERE,DELETE) according to their update function. By transforming FLWD and FLWI on XML view to corresponding SQL (Structure Query Language) on bottom RDB respectively, we can convert the update on XML to update on RDB. At last a synchronized operating mechanism between XML and RDB is set up through the pre-implementation and data lock technology. Through the synchronized data update between XML and RDB, the consistency between XML view and the bottom RDB is assured.