Data mining can be defined as "the process to extract necessary data from a large size of data in the same way as extraction of minerals from mine fields". Clustering is "the process of classifying the objects of same type into different groups". In other words, data set is partitioned into its subsets such that the data for each subset employ some common attributes.The techniques used for data mining can be enforced quickly on different existing stages to improve the value of already existed information assets. These may be evaluated with fresh products and systems as they are purchased online. If implementation on superior client or server processing computers takes place then the tools of data mining can identify large databases to produce answers of the questions like: "Which clients are most likely to respond to my next promotional mailing, and why?"Data mining is much more than just formal data analysis. It utilizes traditional analysis tools like: statistics and graphics tools and those tools which are related to artificial intelligence like: principle induction and neural nets.