EF核心多对多表到另一个表

Question

我对使用EF Core的多对多表有疑问。

假设我有以下情况：

public class Book
{
    public int BookId { get; set; }
    public string Title { get; set; }
    public Author Author { get; set; }
    public ICollection<BookCategory> BookCategories { get; set; }
}  
public class Category
{
    public int CategoryId { get; set; }
    public string CategoryName { get; set; }
    public ICollection<BookCategory> BookCategories { get; set; }
}  
public class BookCategory
{
    public int BookId { get; set; }
    public Book Book { get; set; }
    public int CategoryId { get; set; }
    public Category Category { get; set; }
}

现在，假设我要再创建一个表“ Contracts”，该表应该是“ BookCategory”的子代。

如何建立这种关系？