Querying XML views of relational data

XML has emerged as the standard data exchange format for Internet-based business applications. This has created the need to publish existing business data, stored in relational databases, as XML. A general way to publish relational data as XML is to provide XML views over relational data, and allow business partners to query these views using an XML query language. In this paper, we address the problem of evaluating XML queries over XML views of relational data. This paper makes two main contributions. The first is a general framework for processing arbitrarily complex queries specified using the XQuery query language. The second is a technique for efficiently evaluating XML queries by pushing most of the query computation down to the relational engine.