I don't think there is (or should be) a "default". Default selections suggest they are picked "just because". There is a problem/use-case and a tool to solve it

I don't think there is (or should be) a "default". Default selections suggest they are picked "just because". There is a problem/use-case and a tool to solve it. Sometimes it's relational, sometimes it's nosql, sometimes it's both or even none...