Do you have DBXL installed in two different places, or are you just accessing DAT in two different environments? DAT is simply an interface for DBXL's settings. If you save a Doctype's configuration (with database mappings, etc), and then open DAT somewhere else, but from the same DBXL installation, those settings will still be in place.
If you are looking to move a doctype's configuration from one DBXL installation to another, that can also be done using a tool called the Migration Tool. If that's the case, I can give you a bit more information about that.