如何在 sequelize 中使用内连接

Posted 2023-02-24

【中文标题】如何在 sequelize 中使用内连接

【英文标题】：How to use inner joins in sequilize

【发布时间】：2015-04-02 08:03:54

【问题描述】：

SELECT v.vehicle_id,v.vehicle_model_id,u.user_id,u.first_name FROM user u INNER JOIN user_vehicle v ON u.user_id= v.user_id WHERE u.user_id=3

对于上述查询，我​​使用以下命令

 userModel.find( where: user_id: 3, include: [userVehicleModel] ).success(function(user)
    console.log(user)
)

它给出错误：可能未处理错误：user_vehicle is not associated to user！

提前致谢。

【问题讨论】：

错误信息告诉你出了什么问题——两个模型没有关联。你在 sequelize 中设置了关联吗？

【参考方案1】：

有一个很好的答案here。

简单的工作解决方案：

'use strict';

var Sequelize = require('sequelize');
var sequelize = new Sequelize(/*database*/'test', /*username*/'test', /*password*/'test',
    host: 'localhost', dialect: 'postgres');

var User = sequelize.define('User', 
    firstName: type: Sequelize.STRING,
    lastName: type: Sequelize.STRING
);

var Vehicle = sequelize.define('Vehicle', 
    brand: type: Sequelize.STRING
);

var firstUser;

User.hasMany(Vehicle, constraints: true);
Vehicle.belongsTo(User, constraints: true);

sequelize.sync(force: true)
    .then(function () 
        return User.create(firstName: 'Test', lastName: 'Testerson');
    )
    .then(function (author1) 
        firstUser = author1;
        return Vehicle.create(UserId: firstUser.id, brand: 'Ford');
    )
    .then(function () 
        return Vehicle.create(UserId: firstUser.id, brand: 'Toyota')
    )
    .then(function () 
        return User.findAll(
            where: id: 1,
            include: [Vehicle]
        );
    )
    .then(function displayResults(results) 
        results.forEach(function (c) 
            console.dir(c.toJSON());
        );
    )
    .then(function () 
        process.exit(0);
    );

【参考方案2】：

对于 sequilize 中的一对多关联并获取记录，您只需要编写此查询。

let getuserId = req.query.user_id;
let foundUser await userModel.findOne( 
      where: user_id: getuserId ,
      include: [  model: userVehicleModel  ] )
 );
 if (foundUser) console.log(foundUser);