the Tutorial "Getting started with ASP.NET Core and Entity Framework Core using Visual Studio" at https://docs.microsoft.com/en-us/aspnet/core/data/ef-mvc/index is very useful.
but the version is wrote error at the beginning of the tutorial.
is you use the tutorial, please note that the required version is VS 2017, it use ASP.Net Core 1.1 now.
thks.