如何首先在代码中创建集群键

您基本上需要Person实体之间的多对多关系。为此，您将需要一个连接Person实体对的联结表。如果我们称这个实体为WorkRelationship：

class WorkRelationship
{
    [Key]
    [Column(Order = 1)]
    [ForeignKey("Myself")]
    public int MyselfId { get; set; }

    public virtual Person Myself { get; set; }

    [Key]
    [Column(Order = 2)]
    [ForeignKey("Colleague")]
    public int ColleagueId { get; set; }

    public virtual Person Colleague { get; set; }
}

然后我们Person像这样修改：

class Person
{
    public int Id { get; set; }
    public string Name { get; set; }

    [InverseProperty("Myself")]
    public virtual ICollection<WorkRelationship> WorkRelationships { get; set; }

    public void AddWorkRelationship(Person colleague)
    {
        if (WorkRelationships == null)
        {
            WorkRelationships = new List<WorkRelationship>();
        }

        WorkRelationships.Add(new WorkRelationship { Myself = this, Colleague = colleague });
    }
}

因此，您可以看到Person现在有了的集合WorkRelationships：通过向该集合添加一个实体，您不仅可以将此人链接到他/她的同事，还可以创建反向关系。我还添加了一个辅助方法，以便您可以轻松添加关系。

这是一个非常基本的数据库上下文类，可用于管理这些实体：

sealed class MyContext : DbContext
{
    public DbSet<Person> People { get; set; }
    public DbSet<WorkRelationship> WorkRelationships { get; set; }

    public IEnumerable<Person> GetColleagues(int personId)
    {
        List<WorkRelationship> relationships =
            WorkRelationships
            .Include(x => x.Myself)
            .Include(x => x.Colleague)
            .Where(x => x.MyselfId == personId || x.ColleagueId == personId)
            .ToList();

        foreach (WorkRelationship relationship in relationships)
        {
            if (relationship.Myself.Id == personId)
            {
                yield return relationship.Colleague;
            }
            else if (relationship.Colleague.Id == personId)
            {
                yield return relationship.Myself;
            }
        }
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
        modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();
        modelBuilder.Conventions.Remove<ManyToManyCascadeDeleteConvention>();
    }
}

我还为此添加了一个辅助方法，该方法将检索给定人员的同事。

现在，我们可以创建一个简单的测试程序来插入和查询人员：

static void Main(string[] args)
{
    var alice = new Person { Name = "Alice" };
    var bob = new Person { Name = "Bob" };
    var colin = new Person { Name = "Colin" };
    var davina = new Person { Name = "Davina" };

    alice.AddWorkRelationship(bob);
    alice.AddWorkRelationship(colin);

    bob.AddWorkRelationship(davina);

    using (var db = new MyContext())
    {
        db.People.AddRange(new[] { alice, bob, colin, davina });
        db.SaveChanges();
    }

    using (var db = new MyContext())
    {
        Console.WriteLine("Bob works with:");
        foreach (Person colleague in db.GetColleagues(bob.Id))
        {
            Console.WriteLine(colleague.Name);
        }
    }

    Console.ReadLine();
}

以下是原始答案（包含在上下文中）

如果Colleague is是-a Person，那么您应该像这样建模：

public class Colleague : Person
{
    // don't need any other properties based on what you've posted
}

public class Person
{
    public int Id { get; set; }
    public string Name { get; set; }
    public byte[] Image { get; set; }
    public virtual ICollection<Conversation> Conversations { get; set; }
    public virtual ICollection<Colleague> Colleagues { get; set; }
}

（我将用于保存同事集合的属性名称进行了复数处理）。

然后，EF Code First应该创建一个Person带有Discriminator用于区分Person和Colleague实体的额外列的单个表。

再考虑一下，我什至不确定您是否需要单独的Colleague实体。您可能会摆脱这种情况：

public class Person
{
    ...
    public virtual ICollection<Person> Colleagues { get; set; }
}

请注意，ICollection<Person>而不是ICollection<Colleague>。