EF6：為實體配置復雜映射（代碼優先）

Question

我有兩個db實體，我想使用EF6 Fluent API進行配置。

public class Account
{
    public Int32 Id { get; set; }

    public Int32? LastOperationId { get; set; }
    public virtual Operation LastOperation { get; set; }

    public virtual List<Operation> Operations { get; set; }
}

public class Operation
{
    public Int32 Id { get; set; }

    public Int32? AccountId { get; set; }
    public virtual Account Account { get; set; }
}

對於任何配置，當嘗試將帳戶實體實例插入到數據庫中時，我總是會收到錯誤“無法確定相關操作的有效排序”，如下所示：

var account = new Account();
var operation = new Operation();

account.Operations = new List<Operation>() { operation };
account.LastOperation = operation;

dbContext.Accounts.Add(account);
dbContext.SaveChanges();

Answer 1

幸運的是，EF推斷外鍵列AccountId和LastOperationId ，所以這對我LastOperationId ：

modelBuilder.Entity<Operation>()
.HasKey(x => x.Id)
.HasOptional(x => x.Account)
.WithMany(x => x.Operations);

modelBuilder.Entity<Account>()
.HasKey(x => x.Id)
.HasOptional(x => x.LastOperation);

Answer 2

這是您在Code-First中所需要的組合：

public class Account
{
    // One to one to one relationship (shared PK)
     public int Id { get; set; }

     // One to one to one relationship (shared PK)
     public virtual Operation Operation { get; set; }

    // One to many relationship foreign Key
    [InverseProperty("AccountForList")]
     public virtual List<Operation> Operations { get; set; }
   }

   public class Operation
   {
    // One to one to one relationship (shared PK)
    [ForeignKey("Account")]
     public Int32 Id { get; set; }

     // One to one to one relationship (shared PK)
     public virtual Account Account { get; set; }

     // One to many relationship foreign Key
     public Int32? AccountForListId { get; set; }

     // One to many relationship foreign Key
     [ForeignKey("AccountForListId")]
     public virtual Account AccountForList { get; set; }
     }

帳戶表：columnname：Id

操作表：列名Id（與Account共享），AccountForListId（1..n）