1. A computer system comprising: a storage device that stores a metadata model, wherein the metadata model includes a lower layer and a higher layer, wherein the higher layer and the lower layer each includes one or more model objects, wherein the model objects of the lower layer have a lower degree of abstraction than the model objects of the higher layer, wherein the lower layer provides access to a plurality of different data sources, and wherein the higher layer provides each of a plurality of different business intelligence tools with an interface by which to access each of the plurality of different data sources, and wherein each of the plurality of different business intelligence tools is designed to interface only with a corresponding subset of the plurality of different data sources; and a metadata model transformer configured within a computer to transform the metadata model using a lower-to-higher transformation that obtains information from one of the model objects in the lower layer of the metadata model, abstracts the information by adding business rules for representing a business concept and creates a new model object in the higher layer corresponding to the one of the model objects in the lower layer based on the information abstracted by the abstraction, wherein the new model object in the higher layer provides a representation of the business concept.