在EF4代码中创建多对多关系代码优先

Question

我正在使用EF4 Code-First进行建模，从事ASP.NET MVC中的项目工作。我有以下的模型类：

public class ComicBook 
{ 
    public long ComicBookID { get; set; } 
    public string IssueTitle { get; set; } 
    public int IssueNumber { get; set; } 
    public DateTime PublishDate { get; set; } 

    public IList<ComicBookPerson> Writers { get; set; } 
    public IList<ComicBookPerson> Pencillers { get; set; } 

    public IList<User> CollectingUsers { get; set; } 
} 

public class ComicBookPerson 
{ 
    public long ComicBookPersonID { get; set; } 
    public string Name { get; set; } 

    public IList<ComicBook> WorkedOnComicBooks { get; set; } 
} 

public class User 
{ 
    [Key] 
    public long UserID { get; set; } 
    public string Email { get; set; } 

    public IList<ComicBook> CollectedBooks { get; set; } 
} 

而下面的DbContext：

public class ComicContext : DbContext 
{ 
    public DbSet<ComicBook> ComicBooks { get; set; } 
    public DbSet<ComicBookPerson> ComicBookPerson { get; set; } 
    public DbSet<User> Users { get; set; } 

    protected override void OnModelCreating(DbModelBuilder modelBuilder) 
    { 
     modelBuilder.Entity<ComicBook>() 
      .HasMany(b => b.Writers) 
      .WithMany(w => w.WorkedOnComicBooks) 
      .Map(t => t.MapLeftKey("ComicBookID") 
       .MapRightKey("WriterID") 
       .ToTable("ComicBook_Writers")); 

     modelBuilder.Entity<ComicBook>() 
      .HasMany(b => b.Pencillers) 
      .WithMany(p => p.WorkedOnComicBooks) 
      .Map(t => t.MapLeftKey("ComicBookID") 
       .MapRightKey("PencillerID") 
       .ToTable("ComicBook_Penciller")); 
    } 
} 

的规则，需要应用有：

• 用户可以有很多ComicBooks他们收集
• 漫画书可以在众多用户的收藏中
• 每个漫画书都可以有1个或多个作家
• 每个ComicBook可以有1个或多个Pencillers
• 一个ComicBookPerson可以在任何一本书
• 一个ComicBookPerson可以在很多书工作作家或Penciller，作为一个作家，Penciller，或两者

用户和ComicBooks之间的多对多模式创建得很好。这是多人对ComicBooks和ComicBookPersons之间正在打破。我得到的错误消息是：

Schema specified is not valid. Errors: 
(15,6) : error 0040: Type ComicBook_Writers is not defined in namespace Comics.Models (Alias=Self). 

我基本上想要两个连接表，一个名为ComicBook_Writers，一个名为ComicBookPencillers。这两个表将包含一个ComicBookID和一个ComicBookPersonID。 EF Code First有可能吗？

Answer 1

您需要两个与作家和钢笔者有关的ComicBookPerson类的集合属性。

public class ComicBookPerson 
{ 
    public long ComicBookPersonID { get; set; } 
    public string Name { get; set; } 

    public IList<ComicBook> WroteComicBooks { get; set; } 
    public IList<ComicBook> PenciledComicBooks { get; set; } 
} 

模型映射为

protected override void OnModelCreating(DbModelBuilder modelBuilder) 
{ 
    modelBuilder.Entity<ComicBook>() 
     .HasMany(b => b.Writers) 
     .WithMany(w => w.WroteComicBooks) 
     .Map(t => t.MapLeftKey("ComicBookID") 
      .MapRightKey("WriterID") 
      .ToTable("ComicBook_Writers")); 

    modelBuilder.Entity<ComicBook>() 
     .HasMany(b => b.Pencillers) 
     .WithMany(p => p.PenciledComicBooks) 
     .Map(t => t.MapLeftKey("ComicBookID") 
      .MapRightKey("PencillerID") 
      .ToTable("ComicBook_Penciller")); 
} 

Answer 2

我觉得这样的模式接近是正确的，但仍然失去了一些东西。
的ComicBookPerson既可以是作家和penciller，这意味着你还需要第三列表在ComicBookPerson类：

public IList<ComicBook> WroteComicBooks { get; set; } 
public IList<ComicBook> PenciledComicBooks { get; set; } 
public IList<ComicBook> WrotPencComicBooks { get; set; } 

我说得对不对？