A method operates on a database to extract and present information to a
user. The database comprises data tables containing values of a number of
variables. The information is to be extracted by evaluating at least one
mathematical function which operates on one or more selected calculation
variables. The presented information is to be partitioned on one or more
selected classification variables. The method comprises the steps of
identifying all boundary tables; identifying all connecting tables;
electing a starting table among said boundary and connecting tables;
building a conversion structure that links values of each selected
variable in the boundary tables to corresponding values of one or more
connecting variables in the starting table; and evaluating the
mathematical function for each data record of the starting table, by
using the conversion structure, such that the evaluation yields a final
data structure containing a result of the mathematical function for every
unique value of each classification variable.