如何与Entity Framework Code First建立一对一的关系 [英] How do I establish a one to one relationship with Entity Framework Code First

问题描述

我一直在阅读关于在 EF 中建立一对一关系的人的所有Google和SO页面，但它并不适用于我。 / p>

这是我的模型：

帐户：

  public int Id {get; set;} 
 public virtual AccountConfig AccountConfig {get; set;} 
  

帐户地图：

  HasKey（t => t.Id）; 
 HasRequired（t => t.AccountConfig）
 .WithOptional（）; 
  

帐户配置：

  public int Id {get; set;} 
 public int AccountId {get; set;} 
 public virtual Account Account {get; set;} 
  

帐户配置映射：

  HasKey（t => t.Id）; 
 HasRequired（t => t.Account）
 .WithOptional（t => t.AccountConfig）; 
  

执行时， AccountConfig code>帐户是 NULL ，帐户属性 AccountConfig 是一个不正确的记录（巧合的是，检索到的 Account.Id 与 AccountConfig.Id ，但我不知道这是否意味着什么）。

在数据库中，帐户表没有引用 AccountConfig 记录，但$ code> AccountConfig 表中引用了帐户记录使用 AccountId 列。

最终结果对于我来说，请参考 AccountConfig 从帐户和（如果可能），引用帐户从 AccountConfig 。

解决方案

使用EF，共享主键的表仅支持一对一的关系。您的 AccountConfig 表具有自己的主键，外键为帐户。 EF只支持与此配置的一对多关系。

本文对EF中的1：1和1：0..1关系有一个很好的解释。这里的限制是 EF尚不支持唯一约束的事实的副产品。

I've been reading all the Google and SO pages about people who are establishing a one to one relationship in EF but it just isn't working for me.

Here is my model:

Account:

public int Id {get; set;}
public virtual AccountConfig AccountConfig {get; set;}

Account Map:

HasKey(t => t.Id);
HasRequired(t => t.AccountConfig)
    .WithOptional();

Account Config:

public int Id {get; set;}
public int AccountId {get; set;}
public virtual Account Account {get; set;}

Account Config Map:

HasKey(t => t.Id);
HasRequired(t => t.Account)
    .WithOptional(t => t.AccountConfig);

When executed, the AccountConfig property on Account is NULL and the Account property on AccountConfig is an incorrect record (coincidentally, the retrieved Account.Id is the same as the AccountConfig.Id, but I don't know if that means anything).

In the database, the Account table doesn't have a reference to the AccountConfig record but the AccountConfig table has a reference to the Account record using the AccountId column.

The end result would be for me to have a reference to the AccountConfig from Account and (if possible), a reference to Account from AccountConfig.

解决方案

With EF, one-to-one relationships are only supported on tables that share a primary key. Your AccountConfig table has its own primary key, and a foreign key to Account. EF only supports a one-to-many relationship with this configuration.

This article has a nice explanation of 1:1 and 1:0..1 relationships in EF. The restriction here is a by-product of the fact that EF doesn't yet support unique constraints.

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