1. A system for creating queries on model data of at least one data source in accordance with at least one data source specific format, wherein the system comprises: processing resources including at least one processor and a memory; a graphical query builder configured to enable a user to graphically define a query comprising a plurality of building blocks in accordance with a data source independent format; and a plurality of adapters configured to translate the graphically defined query in the data source independent format into at least one corresponding query in the data source specific format, the plurality of adapters including a first adapter for a first data source configured to translate a portion of the graphically defined query in the data source independent format into a corresponding partial query in the first data source specific format, and a second adapter for a second data source configured to translate another portion of the graphically defined query in the data source independent format into a corresponding partial query in the second data source specific format, wherein the first and second data sources are heterogeneous and at least one of the first and second adapters defines a mapping between objects in the first data source and the second data source.