Data Minig : the practice of examining large pre-existing databases in order to generate new information, it is sorting through data to identify patterns and establish relationships. Data mining techniques are used in a many research areas, including mathematics, cybernetics, genetics and marketing.The predominant activity within the method of knowledge discovery in databases, is anxious with discovering patterns in data. Most commonly, the input to a data mining algorithm is a single table comprising a wide variety of attributes and records. When data from a few tables in a database desires to be taken into consideration, it is left to the user to manage the important tables. In most cases, this effect in a single table, which is then used as input to a data mining algorithm. The output of a data mining algorithm is a pattern or a set of patterns which possibly legitimate within the given data. A pattern is defined as a statement in a given language, that describes the information in a subset of the given data and is less complicated than the enumeration of all suggestions within the subset . Exact guides of sample languages are viewed in data mining: they depend on the data mining enterprise at hand. Natural representatives are equations; classification and regression; and organization, classification, and regression concepts.