1. A method of defining business object models comprising defining plurality of named logical types, field-sets, business objects, structures and enumerations that are referenced in the model by their names, wherein defining the business objects further comprises listing the plurality of their fields, each field having a type attribute referencing a logical type defined in the model, field-sets, each field-set referencing a corresponding field-set defined in the model, and the plurality of business object operations and sub-objects.