Database Interfaces, Implementation and Tests.   SQL Server schema script

Created database interfaces, implementation and tests.  Also added SQL Server schema script.
When I see Impl or similar in a class name, I always think there's a better name available. 
It shouldn't matter to the caller if something is an interface or class, so making the name explicit in the class is not needed. For example in this case, you DBAapter is the interface - that's fine. 
But instead of DBAdapterImpl you could have name that's explicit for example:
MySqlDBAdapter or FileDBAdapter or XMLDBAdapter so drop the Impl and provide something the usefully descriptive.  I know from experience this is not always easy to do, but when it is not easy, it indicates a possible problem with how the interface is being used. In this case, I don't think there is any problem, as it was easy for me to suggestion some better (possible names).  Hopefully this makes some sense, if not, less discuss.