Do you mean business, presentation and data layers? That's a good one although it's good coding design.
If I understand what you mean, I would first look up the differences between the layers. You should be able to use any database and the business/presentation layers don't care. Problem is that the theory doesn't work so well in practice. I worked on an app for the government through an engineering firm and the lead wanted Mongo for development and SQL Server for prod. Disaster.
Layered apps in C# can get complicated. MVC kinda does it on its own between presentation and business logic layers (views and controllers).
Layered apps work well in theory but I've never walked into a place where it works. Usually, it kinda works. They are a good model to follow, but I think C# devs tend to make things a shitfuck more complicated than it needs to be.