Bridging relational technology and xml

XML (extensible Markup Language) is fast emerging as the dominant standard for representing and exchanging information over the Internet. These two key applications of XML lead to exciting database opportunities. If data is stored and represented as XML documents, then it should be possible to query the contents of these documents in order to extract, synthesize and analyze their contents. What is the best way to provide this query capability over XML documents? On the other front, if XML is to serve as the medium for information exchange, then it should be possible to convert data stored in existing database systems into XML form for further processing by web-based applications. How do we effectively publish data in existing database systems as XML documents ? In this dissertation, we tackle these questions, focusing on the use of relational database technology to answer them. In particular, we make two contributions. First, we present a technique for storing and querying XML documents using a relational database system. This technique enables us to efficiently query XML documents by using a sophisticated, high-performance relational query-processor. Second, we propose and evaluate alternative strategies for efficiently publishing existing relational data as XML documents. These strategies enable us to publish XML documents for electronic-commerce applications, where, for the foreseeable future, most business data will almost certainly continue to be stored in relational database systems.