實體框架6更新表並插入到外鍵相關表中

Question

不安靜確定如何為這個標題寫標題，如果不准確，可以隨意編輯。

舉一個例子，我想要完成的是更新表foo中的記錄，然后在后續表中創建新記錄，其中foo表PK為外鍵，請考慮一對多關系。

如何更新具有外鍵約束的表並在這些后續表中創建新的相關記錄？

目前我正在使用Entity Framework 6到.Add和.Attach實體到上下文並將它們保存到數據庫中。

編輯

為了進一步澄清我想要實現的目標，下面的對象是一個減少的例子，我試圖保存到上下文中。 如果我試圖在“Billy Bob”創建之后添加intObj，因為他已經購買了一輛新車，另一項服務，或者他的輪胎已經改變，它將創建一個新的Billy Bob記錄（重復）和相應的相關表。

        intObj.FirstName = "Billy";
        intObj.Lastname = "Bob";
        intObj.Important = 100;
        intObj.LastSeen = DateTime.Now.Date;
        intObj.Cars = new List<Car>{
            new Car{
                Model = "Commodore",
                Make = "Holden",
                YearMade = DateTime.Today.Date,
                Odometer = 15000,
                EmailWordCount = 500,
                TyreStatuss = new List<TyreStatus>{
                    new TyreStatus{
                        Tyre1 = "Good",
                        Tyre2 = "Good",
                        Tyre3 = "Okay",
                        Tyre4 = "Okay"
                        }                                 
                },
                Services = new List<Service>{
                    new Service{
                        Cost = "$500",
                        Time = "2 Days",
                        Date = DateTime.Today
                    }
                },
            }
        };

謝謝

Answer 1

在下面的代碼片段中，您有Employee類，它引用了另外兩個實體：Assignment和一個Country的集合。
像EF，NHibernate等ORM有一個稱為傳遞持久性的特性，也就是說，如果一個對象（賦值和國家）被一個持久的（Employee）引用，那么賦值和國家最終也將成為持久性的，在EF的情況下，SaveChanges方法在Context中被調用，而不是你明確地保存它們。

    public class Employee
        {
            public virtual Guid Id { get; protected set; }
            public virtual string EmployeeNumber { get; set; }
            public virtual Country BirthCountry { get; set; }
            private ICollection<Assignment> _assignment = new List<Assignment>();
            public virtual ICollection<Assignment> Assignments
            {
                get
                {
                    return _assignment;
                }

                set
                {
                    _assignment= value;
                }
            }
        }

        public class Assignment
        {
            public virtual Guid Id { get; protected set; }
            public virtual DateTime BeginTime { get; set; }
            public virtual DateTime EndTime { get; set; }
            public virtual string Description{ get; set; } 
        }

        public class Country
        {
            public virtual Guid Id { get; protected set; }
            public virtual string Name { get; set; }
        }

   //Somewhere in your program      
   private void SaveAllChanges()
         {
             _db = new EFContext();
             //Creating a new employee here, but it can be one loaded from db
             var emp = new Employee { FirstName = "Emp Name", 
                 LastName = "Emp Last", EmployeeNumber = "XO1500"
             };
             emp.BirthCountry = new Country { Name = "Country1" };
             emp.Assignment.Add(new Assignment{ BeginTime = DateTime.Now,EndTime=DateTime.Now.AddHours(1) });

            //Only employee is explicitly added to the context
            _db.Employees.Add(emp); 
            //All the objects in the employee graph will be saved (inserted in this case) in the db. 
            _db.SaveChanges();
        }
    }

編輯：

這與我上面的代碼非常相似，一旦創建了“Billy Bob”，你只需要更新它，包括他購買的任何新服務;

偽代碼：

var bob = _db.Clients.SingleOrDefault(c=> c.Id = "Bob Row Id")
//Bob buy a car:
bob.Cars.Add(new Car()...)
//...and change tire 1 from an old car
var car = bob.Cars.SingleOrDefault(c=> c.Id = "Car Row Id")
car.TireStatus.Tire1 = "New"
....

//Persist all changes
//Existing objects will be updated..., and the new ones created in this process will be inserted
_db.SaveChanges()

如果這澄清了你的想法，請告訴我