1. A computer-readable storage medium storing instructions executable by a computing system to perform a plurality of functions, comprising: receiving a calculation rule presented in a multi-platform expression language to be applied to a data model, the calculation rule being received by one or more of: retrieving the calculation rule from a store of previously-created calculation rules; and accepting user entry of the calculation rule; processing the calculation rule for application to a data model, including: responding to whether the calculation rule is data-driven, including: when the rule is data-driven, determining a condition specified by the calculation rule and performing an action specified by the calculation rule based on the condition; and when the rule is not data-driven, performing the action specified by the calculation rule; identifying a database platform supporting the data model; preprocessing the calculation rule to adapt the calculation rule to operate based on a dimensionality of the data model; upon identifying one or more variables included in the calculation rule, resolving the variables in terms of the data model; and upon identifying one or more parameters included in the calculation rule, soliciting input for the parameters for use in applying the calculation rule to the data model; and executing the calculation rule.