c# - EF 4.3 代码优先 : Table per Type (TPT) with Composite Primary Key and Foreign Key

Question

所以我尝试使用代码优先和 Fluent 将基类映射到一个派生类型，其中表架构是按类型排列的表。此外，派生类型与另一个也具有复合外键的类型具有多对一关系。 (这些表上的键是不可更改的，名称完全匹配。)

这是我试图在 CSharp 中实现的示例:

public class BaseType
{
    public int Id;
    public int TenantId;
    public int Name;
}

public class DerivedType : BaseType
{
    public int Active;
    public int OtherTypeId;
    public OtherType NavigationProperty; 
}

这是配置类中的配置:

public BaseTypeConfiguration()
{
     ToTable("BaseTypes", "dbo");

     HasKey(f => new { f.Id, f.TenantId});

     Property(f => f.Id)
         .HasColumnName("BaseTypeId")
         .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
}

public DerivedTypeConfiguration()
{
    ToTable("DerivedTypes", "dbo");

    //OtherType has many DerivedTypes
    HasRequired(dt=> dt.OtherTypeNavigation)
        .WithMany(ot=> ot.DerivedTypes)
        .HasForeignKey(dt=> new { dt.OtherTypeId, dt.TenantId});
}

据我所知，我的映射设置正确(例如，我遵循了许多具有这种确切情况但具有单个列标识符的教程和示例)

当我尝试查询这些实体时，我得到的异常是: 外键组件“TenantId”不是类型“DerivedType”的声明属性。

当我尝试使用 new 关键字在类型上显式声明这些属性时，我得到一个异常，指出存在重复的属性。

回答 来自 EF 团队的回应

This is part of a more fundamental limitation where EF doesn't support having a property defined in a base type and then using it as a foreign key in a derived type. Unfortunately this is a limitation that would be very hard to remove from our code base. Given that we haven't seen a lot of requests for it, it's not something we are planning to address at this stage so we are closing this issue.

Answer 1

我想这就是您要找的:

[Table("BaseType")]
public class BaseType
{
    [Key, DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
    public int Id {get;set;}
    [Key]
    public int TenantId { get; set; }
    public int Name { get; set; }
}

[Table("Derived1")]
public class DerivedType : BaseType
{
    public int Active { get; set; }
    public int OtherTypeId { get; set; }
    public virtual OtherType NavigationProperty {get;set;}
}

[ComplexType]
public class OtherType
{
    public string MyProperty { get; set; }

}


public class EFCodeFirstContext : DbContext
{
    public DbSet<BaseType> BaseTypes { get; set; }
    public DbSet<DerivedType> DerivedTypes { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<BaseType>().HasKey(p => new { p.Id, p.TenantId });
        base.OnModelCreating(modelBuilder);
    }
}