A middleware approach to storing and querying XML documents in relational databases

In this paper we present a middleware for storing and retrieving XML documents in relational databases. To store XML documents in RDBMS, several mapping approaches can be used. We chose structure independent approach. This approach stores XML documents in fixed-schema tables and does not require a direct extension of SQL. So the middleware can be used with any RDBMS with minor changes in the interface. The middleware offers two alternative methods-namely XRel and Edge- for storing XML in the database. The Edge method is a straightforward method, while XRel utilizes path summary information for faster query processing. We present a comparative experimental study on the performance of insertion and retrieval of two types of XML documents along with a set of XPath queries executed though the XPath query processor which is a part of the middleware.