EF代码优先 - 流畅的API(WithRequiredDependent and WithRequiredPrincipal) [英] EF Code First - Fluent API (WithRequiredDependent and WithRequiredPrincipal)
问题描述
我有以下类:
public class User
{
public Guid Id {get;组; }
public string Name {get;组; }
public夫妇{get;组;
}
public class Couple
{
public Guid Id {get;组; }
public User Groom {get;组; }
public User Bride {get;组;
}
重点:
-
新娘
和Groom
属性是必需的 - 一对一的关系
- 在
User
类中,它是Couple
需要
OnModelCreating中的DbContext
modelBuilder.Entity< User>()。HasRequired(u => u.Couple).WithRequiredPrincipal();
modelBuilder.Entity< Couple>()。HasRequired(u => u.Bride).WithRequiredDependent();
modelBuilder.Entity< Couple>()。HasRequired(u => u.Groom).WithRequiredDependent();
但我不能要求!
数据库中的所有文件都为空。
如何使数据库中的字段不为空?
如果可能,使用API Flient 。
应该是这样的: p>
modelBuilder.Entity< User>()。HasRequired(u => u.Couple).WithRequiredDependent();
modelBuilder.Entity< Couple>()。HasRequired(u => u.Bride).WithRequiredDependent();
modelBuilder.Entity< Couple>()。HasRequired(u => u.Groom).WithRequiredDependent();
HowRequiredDependent如何工作:配置关系需要:在关系的另一边没有导航属性要求。正在配置的实体类型将是依赖关系,并且包含主体的外键。
$
含义:让我们在这里考虑你的第一行代码。它在正在配置的实体(用户)中创建一个外键,使其依赖,并使关系的另一面( Couple )校长
重要提示:你认为你想要的配置会产生一个僵局吗?我没有测试上面的代码,但这个配置似乎是一个死锁给我,所以我不知道如果EF允许你创建它。用户必须需要一对夫妇,而夫妇必须需要同样的用户。
I have the following class:
public class User { public Guid Id { get; set; } public string Name { get; set; } public Couple Couple { get; set; } } public class Couple { public Guid Id { get; set; } public User Groom { get; set; } public User Bride { get; set; } }
Important points:
Bride
andGroom
properties are required- One-to-one relationship
- In the
User
class, it isCouple
requiredDbContext in OnModelCreating
modelBuilder.Entity<User>().HasRequired(u => u.Couple).WithRequiredPrincipal(); modelBuilder.Entity<Couple>().HasRequired(u => u.Bride).WithRequiredDependent(); modelBuilder.Entity<Couple>().HasRequired(u => u.Groom).WithRequiredDependent();
But I can not be required!
All fileds are with null in the database!.
How do I get the fields in the database as not null? If possible using the API Flient.
解决方案It should be this :
modelBuilder.Entity<User>().HasRequired(u => u.Couple).WithRequiredDependent(); modelBuilder.Entity<Couple>().HasRequired(u => u.Bride).WithRequiredDependent(); modelBuilder.Entity<Couple>().HasRequired(u => u.Groom).WithRequiredDependent();
How WithRequiredDependent Works : Configures the relationship to be required:required without a navigation property on the other side of the relationship. The entity type being configured will be the dependent and contain a foreign key to the principal. The entity type that the relationship targets will be the principal in the relationship.
Meaning : Let's consider your first line of code here. It creates a foreign key in the entity being configured (User) making it Dependant and making the other side of the relationship (Couple) Principal
Important : Don't you think the configuration you desire will generate a deadlock? I've not tested the code above, but this configuration seems to be a deadlock to me so i'm not sure if EF would allow you to create it. User must need a Couple, and Couple must need that same user i guess.
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