  XML data warehouses form an interesting basis for decision-support
applications that exploit complex data. However, native-XML database management
systems (DBMSs) currently bear limited performances and it is necessary to
research for ways to optimize them. In this paper, we propose a new join index
that is specifically adapted to the multidimensional architecture of XML
warehouses. It eliminates join operations while preserving the information
contained in the original warehouse. A theoretical study and experimental
results demonstrate the efficiency of our join index. They also show that
native XML DBMSs can compete with XML-compatible, relational DBMSs when
warehousing and analyzing XML data.
