運用群組化節點建構多版本XML文件管理之研究

A Study of Using Grouping Nodes for Multi-Version XML Document Management

近年來，已有許多探討XML文件儲存於關聯式資料庫的技術與文章，但針對多版本XML文件管理機制的研究相形之下就顯的很少。XML文件儲存技術與多版本管理機制上的改善與提昇，除了可增進XML文件使用之便利，亦能擴展XML於相關產業的應用與學術上的研究。為提昇多版本XML文件之查詢與儲存的效能，本研究利用Xing提出的節點群組化方法來建立群組表格並減少搜尋之節點數，應用Dewey索引編碼法以改良節點索引之方法，並導入多版本管理機制，將資料以表格形式儲存於關聯式資料庫中。依據不同XQuery查詢關係，產生規則化之SQL敘述，便可快速地從群組表格中擷取出所需的資料。由於本研究只記錄XML文件的版本差異於群組表格中，故於版本文件儲存上也有很好的效能。

The improvement of the storage technology and the multi-version management not only enhance convenience for using XML documents, but also expand the application of XML in industry and the researches of XML in academy. The study utilizes the grouping nodes method to create the grouping tables and to reduce the number of nodes. Furthermore, we improve the original nodes index method with Dewey order encoding, and we apply the mechanism of multi-version XML document management by storinge the data in tables of the relational database. Depending on the different relation in an XQuery expression, we can generate regulized SQL expressions to quickly retrieve the necessary data from grouping tables. Since we only record the delta information between each version of the XML documents in tables, therefore, the proposed scheme is also very efficient for the multi-version storage.