The main ones are classification, regression analysis, clustering, association rules, feature, change and deviation analysis, Web page mining, etc., which mine data from different perspectives.

Classification is to find out the ****same characteristics of a set of data objects in a database and classify them into different classes according to a classification pattern, the purpose of which is to map the data items in a database to a given class by means of a classification model.

The regression analysis method reflects the characteristics of the attribute values in the transaction database in time, produces a function that maps a data item to a real-valued predictor variable, and discovers the dependence between variables or attributes, and its main research problems include the trend characteristics of the data series, the prediction of the data series, and correlation between the data, and so on.