I'm trying to connect to various customers and map their databases to my database. I need a tool that I can comfortably map their database column/keys to my keys. currently, I'm writing big mapping files in MongoDB that try to map their DB to my DB (including types conversion, and what fields to ignore, and what to map to what... ) but I find it rather complicated... I'm also building a java application running on top of that which is also uncomfortable to read from such a dynamic MongoDB file. Other ideas and tools will be appreciated.