如何将两个类映射到EF Core中的一个表中

Question

public class User 
{ 
    public Account Account { get; set; } 
    public string SomeInfo { get; set; } 
    public Guid Id { get; set; } 
} 

public class Account 
{ 
    public string Name { get; set; } 
} 

public class UserEntityTypeConfiguration : IEntityTypeConfiguration<User> 
{ 
    public virtual void Configure(EntityTypeBuilder<User> builder) 
    { 
     builder.HasKey(x => x.Id); 
     builder 
      .Property(t => t.Id) 
      .ValueGeneratedOnAdd(); 
    } 
} 

我可以映射到一张看起来像这样的表吗？

| Id | SomeInfo | AccountName | 
------------------------------- 
| 1 | info1 | name1  | 
| 2 | info2 | NULL  | 

和映射后，1将映射到：

User.SomeInfo  is "info1" 
User.Account   is not null 
User.Account.Name is "name1" 

和加载2会导致

User.SomeInfo  is "info2" 
User.Account   is null 

谁能帮助？

Answer 1

你想要的东西不能按照你想要的方式完成 - 当使用与所有者位于同一个表中的表拆分/所有实体时，它看起来像EFCore要求相关实体不为空。

我觉得有两个选项 - 共享主键（这将需要两个表和一个急需/显式负载加载与委托人的依赖实体）或逐层次表（TPH）继承（这将需要两个实体类型）。

共享主键：

public class SharedKeyPrincipal 
{ 
    public int Id { get; set; } 
    public int PrincipalProperty { get; set; } 
    public SharedKeyDependent Dependent { get; set; } 
} 
public class SharedKeyDependent 
{ 
    public int Id { get; set; } 
    public int DependentProperty { get; set; } 
    public SharedKeyPrincipal Principal { get; set; } 
} 

modelBuilder.Entity<SharedKeyDependent>() 
    .HasOne(d => d.Principal) 
    .WithOne(p => p.Dependent) 
    .IsRequired() 
    .HasForeignKey<SharedKeyDependent>(d => d.Id); 

var principals = dbContext.Set<SharedKeyPrincipal>() 
    .Include(p => p.Dependent) 
    .ToArray(); 

TPH：

public class InheritanceBaseEntity 
{ 
    public int Id { get; set; } 
    public int BaseEntityProperty { get; set; } 
} 
public class InheritanceDerivedEntity : InheritanceBaseEntity 
{ 
    public int DerivedEntityProperty { get; set; } 
} 

public DbSet<InheritanceBaseEntity> InheritanceBaseEntities { get; set; } 
public DbSet<InheritanceDerivedEntity> InheritanceDerivedEntities { get; set; } 

// use .OfType<InheritanceDerivedEntity>() to get entities that have a 
//  non-null 'value' for the related properties 
var inheritanceEntities = dbContext.Set<InheritanceBaseEntity>().ToArray();