How to fix 'Method 'get_Info' in type 'Oracle.EntityFrameworkCore does not have an implementation.'
I noticed this started happening to me today, some time after I'd already updated to .NET Core 3 for my project and had no issues. Turns out the default scaffolding used when adding an empty mvc controller via solution explorer will add references to EF Core 3 within your web project. I do not use EF Core in our production web projects. For me it was a conflict with the test project we use which uses a different version of EF Core for some database mocking.
Anyway, for the time being I will just not add controllers via the studio options so that does not happen.