A system and method for defining and using logical extensions to a set of data stored in a relational database. A metadata definition for various extensions is stored to explain how to extend data as it is stored into a logical representation suitable for reporting and calculating purposes. An analytical engine translates report requests into SQL queries to access the physically stored data using the metadata extension definitions if necessary to generate appropriate results. Here, data is stored in at least one table that is physically keyed by a set of attributes with the attribute determining the granularity or level of data contained within the tables. A report request causes the engine to calculate and/or display the data at a lower level of granularity than exists, thereby invoking the metadata definitions. The extension definitions may describe how to extend data from the physical to the logical including joins and allocation rules.