Implementation of Multidimensional Index Structures for Knowledge Discovery in Relational Databases

Efficient query processing is one of the basic needs for data mining algorithms. Clustering algorithms, association rule mining algorithms and OLAP tools all rely on efficient query processors being able to deal with high-dimensional data. Inside such a query processor, multidimensional index structures are used as a basic technique. As the implementation of such an index structures is a difficult and time-consuming task, we propose a new approach to implement an index structure on top of a commercial relational database system. In particular, we map the index structure to a relational database design and simulate the behavior of the index structure using triggers and stored procedures. This can easily be done for a very large class of multidimensional index structures. To demonstrate the feasibility and efficiency, we implemented an X-tree on top of Oracle 8. We ran several experiments on large databases and recorded a performance improvement of up to a factor of 11.5 compared to a sequential scan of the database.