1. A computer system, comprising: means for providing mass data associated with banking practice, the mass data comprising data packages, each data package including sets of rows and sets of columns, each row in the set of rows corresponding to a record, and the columns in the set of columns including fields of predetermined granularity characteristics and fields of predetermined key figures; input means for: receiving a selection of predetermined granularity characteristics and predetermined key figures; and receiving a selection of predetermined aggregation operations; and processing means, in communication with the providing means and the input means, for: reading the data packages from the providing means; processing the data packages by identifying the selected granularity characteristics and the predetermined key figures; aggregating the records corresponding to each of the data packages according to the selected granularity characteristics and key figures by using the selected predetermined aggregation operations; forming at least one base matrix comprising the aggregated records corresponding to the selected granularity characteristics and key figures; and calculating specified matrices by using said at least one base matrix.