text: const Sequelize = require('sequelize')
  const sequelize = require('./../index')
  const Student = require('./../models/Student')
  const Course = require('./../models/Course')
  const Selection = sequelize.define(
      'selection', 
      {
          sltid: {
              type: Sequelize.INTEGER, 
              autoIncrement: true, 
              primaryKey: true, 
              unique: true
          },
          student_sid: {
              type: Sequelize.STRING,
              references:{
                  model: 'students',
                  key: 'sid'
              }
          },
          course_cid: {
              type: Sequelize.STRING,
              references:{
                  model: 'courses',
                  key: 'cid'
              }
          },
          select_year: {
              type: Sequelize.INTEGER
          },
          score: {
              type: Sequelize.INTEGER
          }
      }
  );
  Student.hasMany(Selection, { onDelete: 'cascade' });
  Course.hasMany(Selection);
  
  module.exports = Selection;