導軌 - 鏈接現有車型在HABTM

Question

我有兩個型號這樣

class Student 
    has_and_belongs_to_many :classrooms 
end 

class Classrooms 
    has_and_belongs_to_many :students 
end 

我要帶一個學生，聯繫他存在於數據庫中， 每當我試圖做到這一點

類

classroom = Classroom.find(id) 
student = Student.find(id) 
Student.classrooms.create(classroom: classroom) 

我得到這樣的錯誤：

ActiveRecord::UnknownAttributeError: unknown attribute: classroom 

Answer 1

classroom = Classroom.find(classroom_id) 
student = Student.find(student_id) 

classroom.students << student