1. A computer-implemented system for generating at least one report from a plurality of data sources, comprising: a data source specification that indicates the data to be retrieved from the data sources so that a report may be generated based upon the retrieved data, wherein at least two of the data sources are heterogeneous data sources with respect to each other in that one of the data sources supplies its respective data as a data type different than the other data source; a view specification that indicates how the data is to be visually represented within the report; and a report rendering engine having data access to the data source specification and to the view specification, said report rendering engine causing the data to be retrieved from the data sources in accordance with the data source specification, said report rendering engine creating in accordance with the view specification a visual representation of the report based upon the retrieved data.