Connect student_id to submission_id in Rails

问题:

I was trying to connect my student_id to the submission_id, but it's not working. I have a join table which is called submissionstudent.

Student Controller.rb:

class StudentsController < ApplicationController
before_action :set_student, only: [:show, :edit, :update, :destroy]

  # GET /students
  # GET /students.json
  def index
    @students = Student.all
  end

  # GET /students/1
  # GET /students/1.json
  def show
  end

  # GET /students/new
  def new
    @student = Student.new
  end

  # GET /students/1/edit
  def edit
  end

  # POST /students
  # POST /students.json
  def create
    @student = Student.new(student_params)

    respond_to do |format|
      if @student.save
        format.html { redirect_to @student, notice: 'Student was successfully created.' }
        format.json { render :show, status: :created, location: @student }
      else
        format.html { render :new }
        format.json { render json: @student.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /students/1
  # PATCH/PUT /students/1.json
  def update
    respond_to do |format|
      if @student.update(student_params)
        format.html { redirect_to @student, notice: 'Student was successfully updated.' }
        format.json { render :show, status: :ok, location: @student }
      else
        format.html { render :edit }
        format.json { render json: @student.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /students/1
  # DELETE /students/1.json
  def destroy
    @student.destroy
    respond_to do |format|
      format.html { redirect_to students_url, notice: 'Student was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_student
      @student = Student.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def student_params
      params.require(:student).permit(:name)
    end
end

Submission Controller.rb:

class SubmissionsController < ApplicationController
before_action :set_submission, only: [:show, :edit, :update, :destroy]
  before_action :set_form

  # GET /submissions/new
  def new
    @submission = Submission.new

    @all_students = Student.all

    @submission_student = @submission.submissionstudent.build
  end

  # GET /submissions/1/edit
  def edit
  end

  # POST /submissions
  # POST /submissions.json
  def create
    @submission = Submission.new(submission_params)
    @submission.form_id = @form.id

    respond_to do |format|
      if @submission.save
        format.html { redirect_to @form, notice: 'Submission was successfully created.' }
        format.json { render :show, status: :created, location: @submission }
      else
        format.html { render :new }
        format.json { render json: @submission.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /submissions/1
  # PATCH/PUT /submissions/1.json
  def update
    respond_to do |format|
      if @submission.update(submission_params)
        format.html { redirect_to @submission, notice: 'Submission was successfully updated.' }
        format.json { render :show, status: :ok, location: @submission }
      else
        format.html { render :edit }
        format.json { render json: @submission.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /submissions/1
  # DELETE /submissions/1.json
  def destroy
    @submission.destroy
    respond_to do |format|
      format.html { redirect_to submissions_url, notice: 'Submission was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_submission
      @submission = Submission.find(params[:id])
    end

    def set_form
      @form = Form.find(params[:form_id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def submission_params
      params.require(:submission).permit(:conflict, :computer, :extra_time, :am_pm)
    end
end

Model Student.rb:

class Student < ActiveRecord::Base
  has_many :submissionstudent
  has_many :submissions, :through => :submissionstudent
end

Model Submission.rb:

class Submission < ActiveRecord::Base
  belongs_to :form

  has_many :submissionstudent
  has_many :students, :through => :submissionstudent
end

Join table model Studentsubmission.rb:

class Submissionstudent < ActiveRecord::Base
  belongs_to :submission
  belongs_to :student
end

Tell me if you need any more code, Thanks for your help

回答1:

You might need to change the association_name, table_name, model_name and file_names as per the best practices and I am sure it will work

• Model name: Singular CamelCase e.g StudentSubmission
• Model file name: singular snake_case (_ seperated) e.g. student_submission
• Table name: plural submissions
• Join table name: plural e.g. students_submissions # table name in alphabetical order student will come first submission later
• has_many association: plural e.g. student_submissions
• belongs_to and has_one association: Singular e.g. submission

student.rb:

class Student < ActiveRecord::Base
  has_many :student_submissions
  has_many :submissions, :through => :student_submissions
end

submission.rb:

class Submission < ActiveRecord::Base
  belongs_to :form

  has_many :student_submissions
  has_many :students, :through => :student_submissions
end

student_submission.rb:

class StudentSubmission < ActiveRecord::Base
  # join_table_name: students_submissions
  belongs_to :submission
  belongs_to :student
end

also you will need to change the associations where ever you are using them

@student_submission = @submission.student_submissions.build