Javascript Sequelize:TypeError:User.hasMany不是函数

我有这种奇怪的行为。 我有一个用户模型和一个客户端模型。用户有许多客户端。 我正在使用此文档：

当我运行服务器时，Sequelize抛出TypeError:User.hasMany不是一个函数

节点版本：8.9.1
方言：postgres
数据库版本：Postgres 10
续集版本：4.22.15

以下文件都在同一文件夹中

user.js模型

const Sequelize = require('sequelize');
const db = require('../index.js'); //This is an instance of new Sequelize(...)

const tableName = 'users';

const User = db.define('user', {
  firstName: {
    type: Sequelize.STRING(50),
    allowNull: false,
    validate: {
      notEmpty: true
    }
  },
  lastName: {
    type: Sequelize.STRING(50),
    allowNull: false,
    validate: {
      notEmpty: true
    }
  },
  username: { //Username will be the email
    type: Sequelize.STRING(80),
    allowNull: false,
    unique: true,
    validate: {
      isEmail: true
    }
  },
  password: {
    type: Sequelize.STRING,
    allowNull: false,
    validate: {
      notEmpty: true
    }
  },
  isAdmin: {
    type: Sequelize.BOOLEAN,
    allowNull: false,
    defaultValue: false
  },
  isActive: {
    type: Sequelize.BOOLEAN,
    allowNull: false,
    defaultValue: false
  }

}, { tableName });

module.exports = User;

client.js模型

'use strict'

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

const instanceMethods = {
  toJSON() {
    const values = Object.assign({}, this.get());

    return values;
  },
};

const Client = db.define('clients', {
  ibid: {
    type: Sequelize.BIGINT,
    allowNull: true,
    defaultValue: null
  },
  firstName: {
    type: Sequelize.STRING(50),
    allowNull: false,
    validate: {
      notEmpty: true
    }
  },
  lastName: {
    type: Sequelize.STRING(50),
    allowNull: false,
    validate: {
      notEmpty: true
    }
  },
  agreementSigned: {
    type: Sequelize.BOOLEAN,
    allowNull: false,
    defaultValue: false
  },
  totalBalance: {
    type: Sequelize.DECIMAL(11,2),
    allowNull: true,
    defaultValue: null
  },
  currentAllocation: {
    type: Sequelize.STRING,
    allowNull: true,
    defaultValue: null
  }

}, { instanceMethods });

module.exports = Client;

index.js模型

'use strict';

const User = require('./user')
const Client = require('./client');

User.hasMany(Client);
Client.belongsTo(User);

module.exports = {User, Client};

在index.js中， 您尚未导出已初始化的新sequelize实例，因此client.js和user.js无法使用它！define函数作用于您创建的sequelize实例对象

此外，项目中存在循环依赖关系，这可能会造成问题

我试过你的代码，改变了结构，现在可以了！可能还有其他可能的结构，但这一个适合我

1） 不要在index.js中创建sequelize的新实例，而是创建另一个文件作为sequelize实例的初始化

sequelize_index.js（我使用这个文件创建了一个基本实例，然后在客户端和用户模型中使用这个基本实例）

2） client.js看起来像这样

'use strict'
const Sequelize = require('sequelize');

const sequelize=require('./sequelize_index').sequelize;
const db = require('./index.js');

const instanceMethods = {
    toJSON() {
        const values = Object.assign({}, this.get());

        return values;
    },
};

const Client = sequelize.define('clients', {
    ibid: {
        type: Sequelize.BIGINT,
        allowNull: true,
        defaultValue: null
    },
    firstName: {
        type: Sequelize.STRING(50),
        allowNull: false,
        validate: {
            notEmpty: true
        }
    },
    lastName: {
        type: Sequelize.STRING(50),
        allowNull: false,
        validate: {
            notEmpty: true
        }
    },
    agreementSigned: {
        type: Sequelize.BOOLEAN,
        allowNull: false,
        defaultValue: false
    },
    totalBalance: {
        type: Sequelize.DECIMAL(11,2),
        allowNull: true,
        defaultValue: null
    },
    currentAllocation: {
        type: Sequelize.STRING,
        allowNull: true,
        defaultValue: null
    }

}, { instanceMethods });

module.exports = Client;

3） User.js

4） index.js

---

运行index.js后，将创建数据库

在user.js中，您没有导出user

module.exports=user

@Molda很抱歉，我没有复制文件的最终版本，但是是的，我正在正确导出用户模型。我想知道任何其他结构来删除循环依赖项！谢谢！：）@感谢您的回复！我以前可以解决这个问题。我意识到，在使用某种模型之前，我必须需要数据库（我有一个使用User的auth文件，以前我没有包括数据库）。我不太喜欢这种方式，所以明天我会试试你的方式，看起来不错。问候语！

'use strict'
const Sequelize = require('sequelize');

const sequelize=require('./sequelize_index').sequelize;
const db = require('./index.js');

const instanceMethods = {
    toJSON() {
        const values = Object.assign({}, this.get());

        return values;
    },
};

const Client = sequelize.define('clients', {
    ibid: {
        type: Sequelize.BIGINT,
        allowNull: true,
        defaultValue: null
    },
    firstName: {
        type: Sequelize.STRING(50),
        allowNull: false,
        validate: {
            notEmpty: true
        }
    },
    lastName: {
        type: Sequelize.STRING(50),
        allowNull: false,
        validate: {
            notEmpty: true
        }
    },
    agreementSigned: {
        type: Sequelize.BOOLEAN,
        allowNull: false,
        defaultValue: false
    },
    totalBalance: {
        type: Sequelize.DECIMAL(11,2),
        allowNull: true,
        defaultValue: null
    },
    currentAllocation: {
        type: Sequelize.STRING,
        allowNull: true,
        defaultValue: null
    }

}, { instanceMethods });

module.exports = Client;

const Sequelize = require('sequelize');
const sequelize=require('./sequelize_index').sequelize;
const db = require('./index.js'); //This is an instance of new Sequelize(...)

const tableName = 'users';

const User = sequelize.define('user', {
    firstName: {
        type: Sequelize.STRING(50),
        allowNull: false,
        validate: {
            notEmpty: true
        }
    },
    lastName: {
        type: Sequelize.STRING(50),
        allowNull: false,
        validate: {
            notEmpty: true
        }
    },
    username: { //Username will be the email
        type: Sequelize.STRING(80),
        allowNull: false,
        unique: true,
        validate: {
            isEmail: true
        }
    },
    password: {
        type: Sequelize.STRING,
        allowNull: false,
        validate: {
            notEmpty: true
        }
    },
    isAdmin: {
        type: Sequelize.BOOLEAN,
        allowNull: false,
        defaultValue: false
    },
    isActive: {
        type: Sequelize.BOOLEAN,
        allowNull: false,
        defaultValue: false
    }

}, { tableName });

module.exports = User;

'use strict';
const sequelize = require('./sequelize_index').sequelize;
const User = require('./user')
const Client = require('./client');


User.hasMany(Client);
Client.belongsTo(User);

sequelize.sync({force: false}).then(function () {
    console.log("Database Configured");
});
module.exports = {User, Client};