1. A method implemented by a computer in response to execution of program code by a processor of said computer, comprising: receiving a definition of an extension field to be added to a business object node; generating metadata for a data type enhancement object associated with the extension field; and generating an ABAP dictionary proxy object based on the data type enhancement object, wherein the ABAP dictionary proxy object describes the extension field in a sub-structure of a first field of the ABAP dictionary proxy object.