Sequelize db.define 是不是一个函数？

Question

我的续集有问题。我阅读了文档并做同样的事情，但总是遇到以下错误。请帮我解决这个错误。

这是错误

TypeError: db.define 不是函数 在对象。 (/home/robin/Public/server/models/users.js:6:17)

在 Module._compile (internal/modules/cjs/loader.js:1151:30)

在 Object.Module._extensions..js (internal/modules/cjs/loader.js:1171:10)

在 Module.load (internal/modules/cjs/loader.js:1000:32)

在 Function.Module._load (internal/modules/cjs/loader.js:899:14)

在 Module.require (internal/modules/cjs/loader.js:1040:19)

在需要时（内部/模块/cjs/helpers.js:72:18）

在对象。 (/home/robin/Public/server/routes/user.js:4:14)

在 Module._compile (internal/modules/cjs/loader.js:1151:30)

在 Object.Module._extensions..js (internal/modules/cjs/loader.js:1171:10)

在 Module.load (internal/modules/cjs/loader.js:1000:32)

在 Function.Module._load (internal/modules/cjs/loader.js:899:14)

在 Module.require (internal/modules/cjs/loader.js:1040:19)

在需要时（内部/模块/cjs/helpers.js:72:18）

在对象。 (/home/robin/Public/server/app.js:10:19)

在 Module._compile (internal/modules/cjs/loader.js:1151:30)

[nodemon] 应用程序崩溃 - 启动前等待文件更改...

这是代码

模型

const Sequelize = require("sequelizer");
const db = require("../config/database");

const users = db.define("user", {
  email: {
    type: Sequelize.STRING
  } 
});

module.exports = users;

数据库

var fs = require("fs");
var path = require("path");
var Sequelize = require("sequelize");
var basename = path.basename(module.filename);
var env = process.env.NODE_ENV || "development";
var config = require(__dirname + "/../config/config.json")[env];
var db = {};

if (config.use_env_variable) {
  var sequelize = new Sequelize(process.env[config.use_env_variable]);
} else {
  var sequelize = new Sequelize(
    config.database,
    config.username,
    config.password,
    config
  );
}

fs.readdirSync(__dirname)
  .filter(function(file) {
    return (
      file.indexOf(".") !== 0 && file !== basename && file.slice(-3) === ".js"
    );
  })
  .forEach(function(file) {
    var model = sequelize["import"](path.join(__dirname, file));
    db[model.name] = model;
  });

Object.keys(db).forEach(function(modelName) {
  if (db[modelName].associate) {
    db[modelName].associate(db);
  }
});

sequelize
  .authenticate()
  .then(() => {
    console.log("Connection has been established successfully.");
  })
  .catch(err => {
    console.error("Unable to connect to the database:", err);
  });

db.sequelize = sequelize;
db.Sequelize = Sequelize;

module.exports = db;

Answer 1

你的模型

const Sequelize = require("sequelizer");
const db = require("../config/database");

module.exports = (sequelize, Sequelize) => {
const users = db.define("user", {
  email: {
    type: Sequelize.STRING
  } 
})
    return Users
}

Answer 2

应该是这样的

db.sequelize.define("用户",

不是

db.define("用户",

const Sequelize = require("sequelizer");
const db = require("../config/database");

const users = db.sequelize.define("user", {
  email: {
    type: Sequelize.STRING
  } 
});

module.exports = users;

（或）（已更新）

module.exports = (sequelize, Sequelize) => {
const users = sequelize.define("user", {
      email: {
        type: Sequelize.STRING
      } 
    });
 }

别忘了在 Dasebase 文件中导入用户模型 例如：

db.sequelize = sequelize;
db.Sequelize = Sequelize;

    db.users = require('./path/to/usermodel.js')(sequelize, Sequelize);   

module.exports = db;

Answer 3

我遇到了同样的问题，经过一番研究，似乎在使用sequelize-cli 时，生成的models/index.js 文件与所有nodejs 版本都不兼容。

我发现解决此问题的解决方法是将index.js 代码调整为：

const fs = require('fs');
const path = require('path');
const Sequelize = require('sequelize');
const basename = path.basename(module.filename);
const env = process.env.NODE_ENV || 'development';
const config = require('../config/config.json')[env];
const db = {};

let sequelize;
if (config.use_env_variable) {
  sequelize = new Sequelize(process.env[config.use_env_variable]);
} else {
  sequelize = new Sequelize(
    config.database, config.username, config.password, config
  );
}

fs
  .readdirSync(__dirname)
  .filter(file =>
    (file.indexOf('.') !== 0) &&
    (file !== basename) &&
    (file.slice(-3) === '.js'))
  .forEach(file => {
    const model = sequelize.import(path.join(__dirname, file));
    db[model.name] = model;
  });

Object.keys(db).forEach(modelName => {
  if (db[modelName].associate) {
    db[modelName].associate(db);
  }
});

db.sequelize = sequelize;
db.Sequelize = Sequelize;

module.exports = db;

希望这会有所帮助！