Entity Framework：シードメソッドを実行中に新しく作成したレコードのIDを別のレコードに挿入できますか

Question

複数のレコードに対して1つのレコードで作成されたIDを使用しようとすると問題が発生します。

私のモデルは次のようになります。

context.Students.AddOrUpdate(x => x.SID, 
    new WestCobb.Data.Student 
    { 
     SID = "99-B50-404324175", 
     EnrollmentDate = Convert.ToDateTime("01-30-2017"), 
     Active = true, 
     Person = new WestCobb.Data.Person 
     { 
      FirstName = "Brian", 
      LastName = "Folks", 
      AddressId = 4, 
      SSN = 404324175, 
      Addresss = new WestCobb.Data.Address // This address! 
      { 
       StreetAddress = "5076 Lake Charles Court", 
       City = "Chicago", 
       State = "Illinois", 
       ZipCode = 60208 
      } 
     }, 
     Account = new WestCobb.Data.Account 
     { 
      AccountNumber = "M00000000000088", 
      AccountTypeId = 1, 
      Priority = 1, 
      Rate = 225.00m, 
      BillingCycleId = 1, 
      CreateDate = Convert.ToDateTime("01-30-2017"), 
      Active = true 
     } 
    }, 
    // Manually set AddressId of this Person to AddressId of previous Person added 
    new WestCobb.Data.Student 
    { 
     SID = "99-A50-404527896", 
     EnrollmentDate = Convert.ToDateTime("01-30-2017"), 
     Active = true, 
     Person = new WestCobb.Data.Person 
     { 
      FirstName = "Arthur", 
      LastName = "Clue", 
      SSN = 404527896, 
      AddressId = context.Addresses.Last().AddressId // This seems not to work 
     }, 
     Account = new WestCobb.Data.Account 
     { 
      AccountNumber = "W89322198433588", 
      AccountTypeId = 1, 
      Priority = 2, 
      Rate = 225.00m, 
      BillingCycleId = 1, 
      CreateDate = Convert.ToDateTime("01-30-2017"), 
      Active = true 
     } 
    } 
); 

と、次のエラーを取得：データベースをシードするために、以下のものを使用して

public class Student 
{ 
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)] 
    public int StudentId { get; set; } 

    public int PersonId { get; set; } 

    public string SID { get; set; } 

    public int AccountId { get; set; } 

    public bool Active { get; set; } 

    [ForeignKey("PersonId")] 
    public virtual Person Person { get; set; } 

    [ForeignKey("AccountId")] 
    public virtual Account Account { get; set; } 
} 

public class Person 
{ 
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)] 
    public int PersonId { get; set; } 
    public string FirstName { get; set; } 
    public string LastName { get; set; } 
    public string MI { get; set; } 
    public int SSN { get; set; } 
    public int AddressId { get; set; } 
    public int RaceId { get; set; } 

    [ForeignKey("AddressId")] 
    public Address Addresss { get; set; } 
} 

public class Address 
{ 
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)] 
    public int AddressId { get; set; } 
    public string StreetAddress { get; set; } 
    public string City { get; set; } 
    public string State { get; set; } 
    public int ZipCode { get; set; } 
} 

LINQ to Entities does not recognize the method 'WestCobb.Data.Address Last[Address](System.Linq.IQueryable`1[WestCobb.Data.Address])' method, and this method cannot be translated into a store expression. 

を使用することが可能です2番目のPのアドレスに最初のPersonのアドレスが挿入されたときに作成された同じ「id」（AddressId） erson？私は複数のPersonのAddressIdに同じIdを使用したい。

Answer 1

複数のPersonに同じAddressエンティティを使用する場合は、最初にAddressを作成してから何度でも使用してください。

var myAwesomeAddress = new WestCobb.Data.Address() 
{ 
    StreetAddress = "5076 Lake Charles Court", 
    City = "Chicago", 
    State = "Illinois", 
    ZipCode = 60208 
}; 

// You should have a DbSet of your Addresses right ? 
context.Addresses.AddOrUpdate(x => x.Id, // Use any discriminator 
    myAwesomeAddress 
); 

context.Students.AddOrUpdate(x => x.SID, 
    new WestCobb.Data.Student 
    { 
     SID = "99-B50-404324175", 
     EnrollmentDate = Convert.ToDateTime("01-30-2017"), 
     Active = true, 
     Person = new WestCobb.Data.Person 
     { 
      FirstName = "Brian", 
      LastName = "Folks", 
      AddressId = 4, 
      SSN = 404324175, 
      Addresss = myAwesomeAddress 
     } 
    }, 
    new WestCobb.Data.Student 
    { 
     SID = "99-A50-404527896", 
     EnrollmentDate = Convert.ToDateTime("01-30-2017"), 
     Active = true, 
     Person = new WestCobb.Data.Person 
     { 
      FirstName = "Arthur", 
      LastName = "Clue", 
      SSN = 404527896, 
      Address = myAwesomeAddress // here 
     } 
    } 
);