There's going to be a lot of refactoring either way, whether there are custom abstraction layers in place, and whether there aren't. The abstraction layers tha

There's going to be a lot of refactoring either way, whether there are custom abstraction layers in place, and whether there aren't. The abstraction layers that were originally intended to ease a transition between ORMs or DBs often end up making such a transition far more difficult. They just end up being another huge amount of code that needs some type of refactoring.