ruby-on-rails - Rails:ActiveRecord::StatementInvalid 在

Question

我试图在我的 Controller 中使用它来获取与学生(has_many:activities)相关的所有事件(belongs_to:student):

@activities = Activity.joins(:student).where(student: {student_id: @student.id})

但是我收到此错误:

SQLite3::SQLException: no such column: student.student_id: SELECT "activities".* FROM "activities" INNER JOIN "students" ON "students"."id" = "activities"."student_id" WHERE "student"."student_id" = ?

Answer 1

有什么理由不能这样做吗？:

@activities = @student.activities

您的 Student 类(class)应如下所示:

class Student < ActiveRecord::Base

  has_many :activities

end

如果您希望能够直接从 Activity 类访问学生的事件，我建议使用范围。像这样的东西应该有效:

class Activity < ActiveRecord::Base

  scope :for_student, ->(student)  { where(student_id: student) }

end

您可以通过几种不同的方式使用范围:

# pass in the student directly
@activities = Activity.for_student(@student) 

# pass in the student id
@activities = Activity.for_student(@student.id)

# pass in many students
@activities = Activity.for_student([@student1, @student2])