EF6一对一或零关系(Fluent API)

本文关键字：Fluent API 关系 一对一 EF6 | 更新日期: 2023-09-27 18:21:58

我有这样的类（简化）：

public class Transaction
{
    public int LocalId { get; set; }
    public int MachineId { get; set; }
    public virtual Machine Machine { get; set; }       
    public int? MoneyId { get; set; }
    public virtual TransactionMoney Money { get; set; }
}
public class Machine
{
    public int Id { get; set; }
    public string Name { get; set; }
}
public class TransactionMoney
{
    public int LocalId { get; set; }
    public int MachineId { get; set; }
    public virtual Machine Machine { get; set; }
    public int TransactionId { get; set; }
    public virtual Transaction Transaction { get; set; }
}

我希望有关系交易1<->0…1 TransactionMoney，其中Money中的外键应为TransactionId和MachineId（连接到事务的LocalId和MachineId）。我需要用流利的API来做这件事。

我尝试过的是：

    modelBuilder.Entity<Transaction>()
                .HasOptional(t => t.Money)
                .WithRequired(t => t.Transaction)
                .HasForeignKey() <--- there is no such method

另一侧

modelBuilder.Entity<TransactionMoney>()
    .HasRequired(t => t.Transaction)
    .WithOptional(t => t.Money)
            .HasForeignKey() <--- there is no such method

EF6一对一或零关系(Fluent API)

您可以使用类似的东西 
modelBuilder.Entity<TransactionMoney>()
    .HasRequired(t => t.Transaction)
    .WithOptional(t => t.Money)
    .Map(a => a.MapKey("TransactionId", "MachineId"));


事实证明，你所针对的设计无法在EF中完成。我能得到的最接近的如下。但在我离开之前，有一些事情需要注意。从CCD_ 2中移除CCD_ 1字段。CCD_ 3字段从CCD_。外键是用数据注释指定的。如果其中任何一个是不可接受的，就跳过其余部分。

实体：

public class Transaction
{
    public int LocalId { get; set; }
    public int MachineId { get; set; }
    public virtual Machine Machine { get; set; }
    public virtual TransactionMoney Money { get; set; }
}
public class Machine
{
    public int Id { get; set; }
    public string Name { get; set; }
    public virtual ICollection<Transaction> Transactions { get; set; }
    public virtual ICollection<TransactionMoney> Money { get; set; }
}
public class TransactionMoney
{
    public int MachineId { get; set; }
    public virtual Machine Machine { get; set; }
    public int TransactionId { get; set; }
    [ForeignKey("TransactionId,MachineId")]
    public virtual Transaction Transaction { get; set; }
}

配置

modelBuilder.Entity<Transaction>()
    .HasKey(t => new { t.LocalId, t.MachineId })
    .HasRequired(t => t.Machine)
    .WithMany(t => t.Transactions)
    .HasForeignKey(t => t.MachineId);
modelBuilder.Entity<TransactionMoney>()
    .HasRequired(t => t.Machine)
    .WithMany(t => t.Money)
    .HasForeignKey(t => t.MachineId);
modelBuilder.Entity<TransactionMoney>()
    .HasKey(t => new { t.TransactionId, t.MachineId })
    .HasRequired(t => t.Transaction)
    .WithOptional(t => t.Money);
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