Querying XML Documents from a Relational Database in the Presence of DTDs

Many researchers have investigated the problem of storing and querying XML documents using an RDBMS Two situations are considered in this approach based on whether or not an XML schema is available In a schema-oblivious relational approach, an XML schema is not available, or it is available but is not used The advantage of schema-oblivious relational approach is that no XML schema is required, and the fixed generic schema can be used to store XML documents with arbitrary structure However, since XML schema is not exploited, this approach usually implies a query engine where join operations dominate the query time and performance might suffer significantly On the other hand, rare work on the problem of schema-based XML-to-SQL query mapping has been published in the literature In this paper, we present an algorithm to address this problem.