InvalidOperationException when calling SaveChanges in .NET Entity framework

Question

I\'m trying to learn how to use the Entity framework but I\'ve hit an issue I can\'t solve. What I\'m doing is that I\'m walking through a list of Movies that I have and ins

Answer 1

Check if Primary Keys are missing in any of your etities, if yes, then create them, and do the "UpdateModel from Database"

this should Solve the problem