Read this: Many other databases have application software that accesses the database on behalf of end-users, without exposing the DBMS interface directly. Application programmers may use a wire protocol directly, or more likely through an application programming interface. Database designers and database administrators interact with the DBMS through dedicated interfaces to build and maintain the applications' databases, and thus need some more knowledge and understanding about how DBMSs operate and the DBMSs' external interfaces and tuning parameters.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): Who needs less knowledge and understanding about how DBMSs operate?
unanswerable