The most common way you generate such generic functions is by using higher order functions like fmap etc, not by directly coding them using do notation, though

The most common way you generate such generic functions is by using higher order functions like fmap etc, not by directly coding them using do notation, though it is nice to have when you do need it. In languages that have no access to the monad abstraction you'll still need a way to replace your database access with something that you can use during your testing. A monadic database interface won't save you from having to check that your application doesn't do silly things with the database as a side-effect, but it will make it much easier to test that your actual data processing is correct.