15. A system, comprising: a processor and a computer-readable storage medium; a rule interface using the processor that is configured to receive 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; and a run-time system configured to: receive the calculation rule from the rule interface; identify a database platform supporting the data model; wherein the database platform is selected from a group of platforms comprising: a structured query language (SQL) platform that accesses a SQL database in which dimensions and data models are represented as a plurality of tables and a multi-dimensional database platform that accesses a multi-dimensional database in which the dimensions and the data models are stored in a multi-dimensional structure; identify whether the calculation rule includes one more unresolved terms; upon identifying the calculation rule includes one or more unresolved terms, resolving the unresolved terms; adjust the calculation rule for execution on the data model; wherein adjusting the calculation rule comprises determining when the calculation rule accesses more information than the data model provides and determining when to eliminate the calculation rule based on this determination; and identifying whether the calculation rule is data-driven, including: when the calculation 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 calculation rule is not data-driven, performing the action specified by the calculation rule.
15. A system, comprising: a processor and a computer-readable storage medium; a rule interface using the processor that is configured to receive 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; and a run-time system configured to: receive the calculation rule from the rule interface; identify a database platform supporting the data model; wherein the database platform is selected from a group of platforms comprising: a structured query language (SQL) platform that accesses a SQL database in which dimensions and data models are represented as a plurality of tables and a multi-dimensional database platform that accesses a multi-dimensional database in which the dimensions and the data models are stored in a multi-dimensional structure; identify whether the calculation rule includes one more unresolved terms; upon identifying the calculation rule includes one or more unresolved terms, resolving the unresolved terms; adjust the calculation rule for execution on the data model; wherein adjusting the calculation rule comprises determining when the calculation rule accesses more information than the data model provides and determining when to eliminate the calculation rule based on this determination; and identifying whether the calculation rule is data-driven, including: when the calculation 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 calculation rule is not data-driven, performing the action specified by the calculation rule. 19. The system of claim 15 , further comprising a type library, including: one or more rule types from which the calculation rule is derived; and one or more data types from which members of the data model are derived, variable resolvable to the data model, wherein the rule types and the data types are configured to correspond to facilitate application of the calculation rule to the data model.