1. A computer-implemented method for generating an n-dimensional matrix presentation of at least part of an m-dimensional database comprising data records and at least one key dimension, each key dimension comprising a plurality of data value fields, each data value field having real data therein, said method comprising: calculating a sorting sequence of fact numbers consisting of integers, said fact numbers identifying the data records; calculating entry points for each dimension of the n-dimensional matrix presentation, each calculated entry point calculated to be linked with a corresponding fact number of the sorting sequence; calculating a cardinality of the n-dimensional matrix presentation in dependence on the calculated sorting sequence and the calculated corresponding entry points; and generating the n-dimensional matrix presentation based on the calculated cardinality and the calculated entry points.