Most of the information this is stored on computer databases is in a rather raw form. There is a huge amount of information in such databases that may potentially be important, but has not yet been discovered. Data Mining is the extraction of implicit, previously not known, but perhaps useful information from raw data. The idea of data mining is to build some kind of intelligent computer programs searching for regularities or patterns. Data mining algorithms have to be robust in order to deal with noisy, fuzzy and incomplete data. The technical basis of data mining is machine learning including methods from clustering, classification, regression, visualization, decision trees, and artificial neural networks (ANN).