Is it possible to utilize EntityFrameworkCore in VS Code? I've looked around for info on this and it seems that just about every example and tutorial assumes Visual Studio 20xx. Also I don't see Microsoft.EntityFrameworkCore in the Marketplace extensions.
This should solve your problem:
https://docs.microsoft.com/en-us/aspnet/core/tutorials/web-api-vsc?view=aspnetcore-2.0
you need to install:
.NET Core SDK 2.0 or later Visual Studio Code C# for Visual Studio Code