model.hasMany 调用的东西不是 Sequelize.Model 的子类

Posted 2023-03-28

【中文标题】model.hasMany 调用的东西不是 Sequelize.Model 的子类

【英文标题】：model.hasMany called with something that's not a subclass of Sequelize.Model

【发布时间】：2022-01-04 23:16:39

【问题描述】：

每当我尝试从无服务器框架 lambda 调用任何调用时，我都会收到以下错误

[offline] _____ HANDLER RESOLVED _____
offline: Failure: product.hasMany called with something that's not a subclass of Sequelize.Model
Error: product.hasMany called with something that's not a subclass of Sequelize.Model
    at Function.hasMany (C:\Users\Kiran\Documents\Projects\Rentals-Backend\node_modules\sequelize\lib\associations\mixin.js:18:13)
    at Function.Product.associate (C:\Users\Kiran\Documents\Projects\Rentals-Backend\entity\product.js:21:17)

IMPORTANT

以下代码是上述错误的答案。您可能错过了任何步骤。所以你可以参考和修复。感谢Anatoly帮助我解决问题。

产品型号：

const  STRING, BOOLEAN, INTEGER  = require("sequelize");

module.exports = (sequelize, DataTypes) => 
    const Product = sequelize.define("product", 
        id:  type: INTEGER, primaryKey: true, autoIncrement: true ,
        name:  type: STRING ,
        description:  type: STRING, allowNull: true ,
        purchase_price:  type: STRING ,
        tax:  type: STRING ,
        sale_price:  type: STRING ,
        categoryId:  type: STRING ,
        status:  type: BOOLEAN, defaultValue: 0 ,
        created_on:  type: INTEGER, allowNull: true ,
        updated_on:  type: INTEGER, allowNull: true ,
    , 
        timestamps: false,
        freezeTableName: true,
    )
    Product.associate = function (models) 
        Product.hasMany(models.product_image,  as: "images" );
        Product.belongsTo(models.product_category,  as: "category", foreignKey: 'categoryId' );
    ;
    return Product;

图像模型：

const  STRING, BOOLEAN, INTEGER  = require("sequelize");

module.exports = (sequelize, DataTypes) => 
    const ProductImage = sequelize.define("product_image", 
        id:  type: INTEGER, primaryKey: true, autoIncrement: true ,
        productId:  type: INTEGER ,
        fileName:  type: STRING ,
        url:  type: STRING ,
        position:  type: INTEGER ,
        isDefault:  type: BOOLEAN, defaultValue: 0 ,
        shopId:  type: STRING ,
        status:  type: BOOLEAN, defaultValue: 0 ,
        created_on:  type: INTEGER, allowNull: true ,
        updated_on:  type: INTEGER, allowNull: true ,
    , 
        timestamps: false,
        freezeTableName: true,
    )

    return ProductImage;

类别模型：

const  STRING, BOOLEAN, INTEGER  = require("sequelize");


module.exports = (sequelize, DataTypes) => 
    const ProductCategory = sequelize.define("product_category", 
        id:  type: INTEGER, primaryKey: true, autoIncrement: true ,
        name:  type: STRING ,
        description:  type: STRING, allowNull: true ,
        status:  type: BOOLEAN, defaultValue: 0 ,
        created_on:  type: INTEGER, allowNull: true ,
        updated_on:  type: INTEGER, allowNull: true ,
    , 
        timestamps: false,
        freezeTableName: true,
    );
    return ProductCategory;

这是我们初始化 sequelize 的配置文件

配置文件

    const Sequelize = require('sequelize')
    const fs = require('fs')
    const path = require('path')
    const db = 
    const models = path.join(__dirname, '..', 'entity')
    var basename = path.basename(module.filename)
    
    const sequelize = new Sequelize(
        process.env.DB_NAME,
        process.env.DB_USER,
        process.env.DB_PASSWORD,
        
            dialect: 'mysql',
            host: process.env.DB_HOST,
            port: process.env.DB_PORT,
            logging: false
        
    )
    
    fs
      .readdirSync(models)
      .filter(function (file) 
        return (file.indexOf('.') !== 0) && (file !== basename) && (file.slice(-3) === '.js')
      )
      .forEach(function (file) 
        var model = require(path.join(models, file))(
          sequelize,
          Sequelize.DataTypes
        );
        db[model.name] = model;
        
      )
    
    Object.keys(db).forEach(function (modelName) 
      if (db[modelName].associate) 
        db[modelName].associate(db)
      
    )
    
    db.Sequelize = Sequelize
    db.sequelize = sequelize
    
    module.exports = db

我们在这里调用产品详细信息。

调用函数

    const db = require('../config/sequelize-config');
    exports.getProductById = (query, username, shopId) => 
        return new Promise((resolve, reject) => 
            db.product.findOne(
                where: 
                    id: query.id
                ,
                attributes: ['id', 'name', 'description', ['purchase_price', 'purchasePrice'], 'tax', ['sale_price', 'salePrice']],
                include: [
                    model: db.product_image,
                    as: 'images',
                    where: 
                        status: 1
                    ,
                    required: false,
                    attributes: ['id', 'fileName', 'position', 'url']
                ,
                
                    model: db.product_category,
                    as: 'category',
                    required: false,
                    attributes: ['id', 'name']
                ]
            ).then(product => 
                if (product) 
                    resolve( [KEY_STATUS]: 1, [KEY_MESSAGE]: "Product details fetched successfully", [KEY_DATA]: product );
                 else 
                    reject( [KEY_STATUS]: 0, [KEY_MESSAGE]: "Product details fetch failed" );
                
            ).catch(error => 
                reject( [KEY_STATUS]: 0, [KEY_MESSAGE]: "Product details fetch failed", [KEY_ERROR]: error.message );
            );
        )
    

【参考方案1】：

为避免交叉引用错误和类似错误，我建议将模型定义转换为函数并在同一个模块中注册模型和关联，请参阅this answer 和问题

【讨论】：

尝试了几个小时后，我收到了TypeError: Cannot read property 'define' of undefined

您能否用修改后的模型文件和注册模块更新您的问题？

我在底部添加了Config file 和calling funtion。但是错误来自category model文件let categoryModel = db.sequelize.define("product_category", 这一行。

你没有像这里那样把你的模型定义变成函数：***.com/a/61710568/1376618

另外，我再次参考了文档，不会提及问题或注意事项。