static void Main(string[] args) { ProductDbObject product1 = new ProductDbObject() { Category = new CategoryDbObject() { Name = "Pizza", PrimaryKey = new Guid() }, Name = "JakasTam", PrimaryKey = new Guid() }; CategoryDbObject PizzaCategory = new CategoryDbObject() { Name = "Pizza", PrimaryKey = new Guid() }; CategoryService catgeService = new CategoryService(new HtcEfDbContext()); catgeService.AddEntity(PizzaCategory); catgeService.SaveChange(); }