自指联想

Question

这是this.的后续问题

这是我目前建立师生关系的背景.

用户模型

  has_many :teacher_links, :foreign_key => :student_id, :dependent => :destroy, :class_name => "TeacherStudentLink"
  has_many :student_links, :foreign_key => :teacher_id, :dependent => :destroy, :class_name => "TeacherStudentLink"
  has_many :students, :through => :student_links
  has_many :teachers, :through => :teacher_links

TeacherStudentLink模型

class TeacherStudentLink < ActiveRecord::Base
  attr_accessible :user_id, :student_id, :teacher_id

  belongs_to :user
  belongs_to :student, :class_name => "User"
  belongs_to :teacher, :class_name => "User"
end

我觉得很尴尬，因为teacher_student_links表有三列:用户、学生、教师。用户可以有很多老师，他也可以有很多学生。如果我没有教师专栏，而只是假装“用户”是“老师”，一切都很完美。有办法解决这个问题吗？

Answer 1

奶酪黄鼠狼在评论中说，你的链接不应该有user_id

class TeacherStudentLink < ActiveRecord::Base
  attr_accessible :student_id, :teacher_id

  belongs_to :student, :class_name => "User", :foreign_key => :student_id
  belongs_to :teacher, :class_name => "User", :foreign_key => :teacher_id
end

• belongs_to foreign_key指定当前表(链接)上的外键
• has_many foreign_key指定另一个表(链接)上的外键