1. DATA WAREHOUSING

Clustering is a useful technique for discovery of data distribution and patterns in the underlying data. The goal of clustering is to discover dense and sparse regions in a data set. Data clustering has been studied in the statistics, machine learning, and database communities with diverse emphases. There are two main types of clustering techniques partitional clustering techniques and hierarchical clustering techniques. The partitional clustering techniques construct a partition of the database into predefined number of clusters. The hierarchical clustering techniques do a sequence of partitions in which each partition is nested into next partition in the sequence.