错误：hasMany调用的不是Sequelize.Model的子类

Question

我正在尝试创建仅由两个外键SEATS_ID和SCREENING_ID组成的表OCCUPIED_SEATS，这两个外键均构成唯一索引。

如何在Sequelize中做到这一点？

我尝试在OCCUPIED_SEATS和其他文件的FK中创建索引。

const SEATS = require("./Seats");
const SCREENING = require("./Screening");

const OCCUPIED_SEATS = sequelize.define("OCCUPIED_SEATS", {
    //SEATS_ID
    //SCREENING_ID
  },
  {
    indexes: [
      {
        unique: true,
        fields: [SEAT_ID, SCREENING_ID]
      }
    ],
    underscored: true
  }
);

OCCUPIED_SEATS.belongsTo(SEATS, {foreignKey: 'SEAT_ID'});

OCCUPIED_SEATS.sync();
module.exports = OCCUPIED_SEATS;

---

const OCCUPIED_SEATS = require("./Occupied_Seats");


const SEATS = sequelize.define("SEATS", {
    //ROOM_ID
    SEATS_ID: {       
      type: Sequelize.INTEGER,
      primaryKey: true,
      allowNull: false,
      autoIncrement: true
    },
    ROW: {
        type: Sequelize.STRING,
        allowNull: false,
    },
    COLUMN: {
        type: Sequelize.INTEGER,
        allowNull: false
    },
  },
  {
    underscored: true
  }
);

SEATS.hasMany(OCCUPIED_SEATS, {foreignKey: 'SEAT_ID'});

module.exports = SEATS;

我得到以下错误。

错误：SEATS.hasMany调用的不是Sequelize.Model的子类。