Implementing a database programming language for XML applications

There is an emerging amount of software for generating, manipulating and storing XML documents, which remain valid according to a given DTD or an XML Schema. Common solutions are often based on the W3C’s Document Object Model (DOM), which has evolved to an important collection of language independent interfaces allowing to represent and manipulate any single XML document. Databases containing many XML documents are not covered. The main focus of this paper is the implementation of a database programming language for XML applications providing multi-document-access. XOBEDBPL is a statically typed DataBase Programming Language based on XOBE (XML OBjEcts) and Java. XOBE integrates XML and XPath into Java and guarantees the validity of processed XML structures against an XML Schema or DTD at compile time. In XOBEDBPL XML objects can now become persistent. XOBEDBPL additionally integrates xFLWOR(extended FLWOR) expressions to manipulate and query persistent XML. Implementing XOBEDBPL using an extended version of the DOM (xDOM) offers the possibility to query and update whole databases consistently. Experimental results with XOBEDBPL and a multi-document database generated by the XBench(Yao et al,2004) project are provided.