避免循环或多个级联路径

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我经历了很多帖子here，here和here不见了。但是没有一篇文章提出了适当的解决方案。我想知道这种情况怎样才能切实解决。

我Models和Contexts如下：

public class Context : DbContext 
    { 
     public Context() : base("DefaultConnection") 
     { 
     } 
     public DbSet<Student> Students { get; set; } 
     public DbSet<Course> Courses { get; set; } 
     public DbSet<Staff> Staffs { get; set; } 
    } 

public class Student 
    { 
     public int StudentId { get; set; } 
     public string FirstName { get; set; } 
     public string LastName { get; set; } 
     [Required] 
     public virtual Course Course { get; set; } 
     [Required] 
     public virtual Staff Staff { get; set; } 

    } 


public class Staff 
     { 
      public int StaffId { get; set; } 
      public string Name { get; set; } 
      public string Contact { get; set; } 
     } 


public class Course 
    { 
     public int CourseId { get; set; } 
     public string CourseName { get; set; } 
     [Required] 
     public virtual Staff Staff { get; set; } 
    }

我正在上线此异常：

context.Students.Add(student);

下面的代码的

：

public void AddStudent() 
     { 
      Student student = new Student(); 
      student.FirstName = "Bruce"; 
      student.LastName = "Wayne"; 
      student.Course = new Course(); 
      student.Course.CourseName = "CSE"; 
      student.Course.Staff = new Staff(); 
      student.Course.Staff.Name = "Albert"; 
      student.Course.Staff.Contact = "1234567890"; 
      context.Students.Add(student); 
      context.Courses.Add(student.Course); 
      context.SaveChanges(); 
      Console.WriteLine("Student , Course, Staff Added"); 
     }

来源

2012-12-31 Bhushan Firake

希望你的'学生'表看起来像？你有触发器还是简单地级联删除/更新表？ –

@GustavKlimt我首先使用实体框架模型。我的模型如上所述，到目前为止没有触发器 –