Sequelize hasMany 工作正常，但反比关系不起作用

Question

我正在尝试使用 Sequelize 在 Node Js(express Js) 中处理 mysql 关系。

User.hasMany(Post); 工作得很好，但是当我尝试在 Post 模型中反转它时：Post.belongsTo(User);

收到此错误： throw new Error(${source.name}.${_.lowerFirst(Type.name)} 调用的东西不是 Sequelize.Model 的子类);

错误：post.belongsTo 调用的东西不是 Sequelize.Model 的子类

用户模型如：

const Sequelize = require('sequelize');
const db = require('../config/db');

const Post = require('./Post');

const User = db.define('user', {
    id: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        notNull: true,
        primaryKey: true
    },
    name: {
        type: Sequelize.STRING,
        notNull: true
    },
    email: {
        type: Sequelize.STRING,
        notNull: true
    },
    password: {
        type: Sequelize.STRING,
        notNull: true
    }

});

User.hasMany(Post);

module.exports = User;

和 Post 模型一样：

const Sequelize = require('sequelize');
const db = require('../config/db');

const User = require('./User');

const Post = db.define('post', {
    id: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        notNull: true,
        primaryKey: true
    },

    title: {
        type: Sequelize.STRING,
        notNull: true
    },
    description: {
        type: Sequelize.TEXT,
        notNull: true
    },
    author: {
        type: Sequelize.STRING,
        notNull: true
    }
});

Post.belongsTo(User);

module.exports = Post;

我该如何解决这个问题？ 谢谢大家...

Answer 1

您应该更正您的模型定义导出为函数，并像这样在每个模型定义函数中定义 associate 函数，并在所有模型都注册到诸如 database.js 之类的模块中之后调用它：

user.js

module.exports = (sequelize, DataTypes) => {
  const User = sequelize.define('user', {
    id: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        notNull: true,
        primaryKey: true
    },
   ...

  User.associate = function (models) {
    User.hasMany(models.Post)
  }

post.js

module.exports = (sequelize, DataTypes) => {
  const Post = sequelize.define('post', {
    id: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        notNull: true,
        primaryKey: true
    },
  ...
  Post.associate = function (models) {
    Post.belongsTo(models.User)
  }