In the situation when you develop your database gradually along with your ASP.NET Core project, you will end up in the situation where you need to add additional entities to your application, other than the ones you developed in day 1.
Now, in order not to loose all the changes that you done to the existing models, like validation decorations, you have the option to use the -t parameter when doing scaffolding.
An example of a command that it is updating the Models only with the selected tables can be seen below:
Scaffold-DbContext "Data Source=NOTEBOOK\SQLEXPRESS;Initial Catalog=Articles;Integrated Security=True" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models -t ArticleType, Article -f
Now, there is a caveat: When you execute the above command, the DBContext class, will be rewritten and it will contain only the newly added entities.
However, as a workaround, you can do first a backup of the file, and after the new file is generated, you can add in the code for the new entities.