Question

我想使用代码优先方法使用EF 6创建多对多关系。我的实体使用复合主键（处理多租户）。

让我们采取简单而经典的例子。我有两个实体Project和Person，它们具有多对多关系：

public class Person
{
   [Key, Column(Order = 1),]
   public Int32 Id { get; set; } 
   [Key, Column(Order = 2)]
   public int TenantId { get; set; }
   public string Name { get; set; }
}

public class Project
{
   [Key, Column(Order = 1),]
   public Int32 Id { get; set; } 
   [Key, Column(Order = 2)]
   public int TenantId { get; set; }
   Public string Name { get; set; }
}

我也有这样的加入表ProjectPerson：

上面我定义了Project到ProjectPerson的关系。注意公共类ProjectPerson { [Key，Column（Order = 1），] public Int32 Id {get;组; } [Key，Column（Order = 2）] [ForeignKey的（＆＃34;项目＆＃34）] public int TenantId {get;组; }

   [ForeignKey("Project")]
   public int ProjectId { get; set; }

   public DateTime AddedDate{ get; set; }

   public virtual Project Project { get; set; }
}

TenantId用作主键和外键的一部分。

到目前为止，该模型按预期工作。但是缺少Person到ProjectPerson的关系。

我已将以下两行添加到ProjectPerson类

  [ForeignKey("Person")]
  public int PersonId { get; set; }

  public virtual Person Person { get; set; }

缺少绝对映射到TenantId。我不知道如何定义它

更新

我找到了这个。但仍然不满意，因为有额外的TenantId（PersonTenantId）作为外键。

 public class ProjectPerson
 {
   [Key, Column(Order = 1),]
   public Int32 Id { get; set; } 
   [Key, Column(Order = 2)]
   [ForeignKey("Project")]
   public int TenantId { get; set; }

   [ForeignKey("Project")]
   public int ProjectId { get; set; }

   [ForeignKey("Person")]
   public int PersonId { get; set; }
   [ForeignKey("Person")]
   public int PersonTenantId { get; set; } // duplicate 


   public DateTime AddedDate{ get; set; }

   public virtual Project Project { get; set; }
   public virtual Person Person { get; set; }

}

Answer 1

Use the fluent API to reuse the TentantId column for both FK's in the junction table. ProjectId should also be included in the junction table's PK. Note that I modified the order of the composite primary key columns to have TenantId as the first column.

    public class Person
    {
        [Key, Column(Order = 0)]
        public int TenantId { get; set; }
        [Key, Column(Order = 1)]
        public int PersonId { get; set; }

        public string Name { get; set; }

        public virtual ICollection<ProjectPerson> ProjectPeople { get; set; }
    }

    public class Project
    {
        [Key, Column(Order = 0)]
        public int TenantId { get; set; }
        [Key, Column( Order = 1 )]
        public int ProjectId { get; set; }

        public string Name { get; set; }

        public virtual ICollection<ProjectPerson> ProjectPeople { get; set; }
    }

    public class ProjectPerson
    {
        [Key, Column( Order = 0 )]
        public int TentantId { get; set; }
        [Key, Column( Order = 1 )]
        public int ProjectId { get; set; }
        [Key, Column( Order = 2 )]
        public int PersonId { get; set; }

        public DateTime AddedDate { get; set; }

        public virtual Project Project { get; set; }
        public virtual Person Person { get; set; }
    }


    protected override void OnModelCreating( DbModelBuilder modelBuilder )
    {
        base.OnModelCreating( modelBuilder );

        modelBuilder.Entity<Project>()
            .HasMany(pr => pr.ProjectPeople )
            .WithRequired( pp => pp.Project )
            .HasForeignKey( pp => new { pp.TentantId, pp.ProjectId } );

        modelBuilder.Entity<Person>()
            .HasMany( pe => pe.ProjectPeople )
            .WithRequired( pp => pp.Person )
            .HasForeignKey( pp => new { pp.TentantId, pp.PersonId } );
    }

EF在同一主键上有多个外键关系

1 个答案: