This article presents the ways of identification, selection and transformation of the data into other structures. Relation selection and transformation may change data quantity and order of laying out. As a result the data are aggregated to the structure needed for application problem algorithm. Data aggregation makes possible to adapt data structure presentation order and quantity for any application problem. Naturally, there must be enough necessary data in the relation sets for any application problem. Key words: input data, application problem, data sets, relation.