What is the best way to keep the connection string for a database connection in a central (change it only in one place to change everywhere) location?
Take advantage of migrations in EF Core to manage database schema changes over time and keep them in sync with the data models of your ASP.NET Core applications. An object-database mapper for .NET ...
You want to give the user the ability to select one (or more) items from a table. It's not as easy in ASP.NET MVC as you might like... but it's not awful, either. You have a table on your ASP.NET MVC ...