I'm in agreement with Patrick. CM is not really a subset of anything else as it is intended to capture everything that can add value to a company. You can add to, but not limit Patricks list, to the addition of Test cases, par files, support rotas, licensing information etc
I'm also in agreement with his references to test data
Personally, I feel CM is a discipline that controls scope at a system and/or business level. DM is a very broad term, as in: anything that involves planning, analysis, development, implementation, and maintenance of systems to process data. DM has so many definitions depending on the person or group defining it.