| 摘要 |
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, i.e. data tables containing at least one value of one of the selected variables; identifying all connecting tables, i.e. data tables that have variables in common with the boundary tables and connect the same; 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. |
