Abstract. The aim of this article is to explore and investigate possibilities of reuse already known techniques from object and objectoriented processing for effective processing in XML-native database systems. The article provides explanation of impedance problem, specifically impedance mismatch problem of the middleware, semi-orthogonal persistency methods, and also presents results of experiments with XML:DB API implementation over GOODS object persistent data storage and JAXB technology which were done in January 2006 on Dept. of Computer Science FEE CTU in Prague.