Question: what are csdl ssdl and msl?
Answer: CSDL (Conceptual Schema definition language) is the conceptual abstraction which is exposed to the application. SSDL (Storage schema definition language) defines the mapping with your RDBMS data structure. MSL ( Mapping Schema language ) connects the CSDL and SSDL. CSDL, SSDL and MSL are actually XML files.