配置實體

Question

之間的多重關係，我有Person和Course實體多重關係：

public class Course 
{ 
    public int CourseID { get; set; } 
    public virtual Person Leader { get; set; } 
    public virtual ICollection<Person> Teachers { get; set; } 
    public virtual Person CreatedBy { get; set; } 
    public virtual Person UpdatedBy { get; set; } 
    ... 
} 

public class Person 
{ 
    public int PersonID { get; set; } 
    public virtual ICollection<Course> CoursesCreated { get; set; } 
    public virtual ICollection<Course> CoursesUpdated { get; set; } 
    public virtual ICollection<Course> CoursesLead { get; set; } 
    public virtual ICollection<Course> CoursesTutored { get; set; } 
    ... 
} 

我有以下映射：

modelBuilder.Entity<Course>().HasMany(x => x.Tutors) 
          .WithMany(p => p.CoursesTutored) 
          .Map(x => 
           { 
            x.MapLeftKey("PersonID"); 
            x.MapRightKey("CourseID"); 
            x.ToTable("Course_Tutors"); 
           }); 

這工作，因爲它建立了Course_Tutors表以及如提供Leader_PersonID，CreatedBy_PersonID和UpdatedBy_PersonID的課程表。

但是，它還在課程表中創建了三個額外的Person列：Person_PersonID1，Person_PersonID2,Person_PersonID3。

有人能告訴我如何擺脫這些？我假設我的映射需要更多的工作。

Answer 1

當您在兩個實體之間存在多個關係時，Code First存在通過轉換來識別關係的問題。你需要明確地配置它們。

modelBuilder.Entity<Course>() 
    .HasRequired(c => c.Leader) 
    .WithMany(p => p.CoursesLead) 
    .Map(m => m.MapKey("Leader_PersonID")); 

modelBuilder.Entity<Course>() 
    .HasRequired(c => c.CreatedBy) 
    .WithMany(p => p.CoursesCreated) 
    .Map(m => m.MapKey("CreatedBy_PersonID")); 

modelBuilder.Entity<Course>() 
    .HasRequired(c => c.UpdatedBy) 
    .WithMany(p => p.CoursesUpdated) 
    .Map(m => m.MapKey("UpdatedBy_PersonID"));