EF 4.1 RC EF CF中的许多关系 [英] EF 4.1 RC Many to many relationship in EF CF

问题描述

我有两个实体有这么多的关系：

I have two entities with many to many relationship like this:

class author
{
  public int AuthorID{get;set;}
  public string Name{get;set;}
  public virtual ICollection<book> books{get;set;}
}
class book
{
  public int BookID{get;set;}
  public string Name{get;set;}
 public virtual ICollection<author> authors{get;set;}

}

我有一个中间表名为Bookauthor的表如下定义：

and I have an intermediate table named Bookauthor defined like this:

  BookAuthor: int
  int AuthorID
  int BookID

如何使用FluentAPI进行映射

How to map this using FluentAPI

谢谢!!

推荐答案

这与EDMX有问题，但EF 4.1流畅的API 可以映射：

This was problematic with EDMX but with EF 4.1 fluent API you can map it:

modelBuilder.Entity<book>()
            .HasMany(b => b.authors)
            .WithMany(a => a.books)
            .Map(m => m.MapLeftKey("BookID")
                   .MapRightKey("AuthorID")
                   .ToTable("BookAuthor"));

正如您所看到的，我不会映射 BookAuthor 列。该列对于EF是未知的，必须自动递增。

As you can see I don't map BookAuthor column. That column is unknown to EF and must be auto incremented.

这显然无法使用Code-first方法，但只有当您使用Fluent API与现有数据库时。

This obviously can't work with a Code-first approach but only if you use Fluent API against existing database.

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