Question

我正在使用sequelize在我的node.js项目中创建一个数据库。到目前为止，我只使用了beforeTo和hasOne，它们运行良好。但是，现在我需要创建多对多关系，我有点困惑，后遗症无法正确地使用“槽”属性解释我的belongsToMany。任何帮助，将不胜感激。干杯！

定义所有关系的索引文件

const express = require('express');
const app = express();

const sequelize = require('./db/database');
const User = require('./models/User');
const Tenant = require('./models/Tenant');
const Role = require('./models/Role');
const Class = require('./models/Class');
const Level = require('./models/Level');
const Subject = require('./models/Subject');
const Student = require('./models/Student');
const Contact = require('./models/Contact');
const StudentContact = require('./models/StudentContact');

const userRoutes = require('./routes/user');
const authRoutes = require('./routes/auth');
const tenantRoutes = require('./routes/tenant');

const seed = require('./db/seed');

const port = process.env.PORT || 8080;

// allows node to parse querystrings
app.use(express.json({ extended: false }));

// routes for our endpoints
app.use('/api/auth', authRoutes);
app.use('/api/users', userRoutes);
app.use('/api/tenant', tenantRoutes);

// sets up the role and tenant relationships to the user.
User.belongsTo(Tenant, { foreignKey: { allowNull: false } });
User.belongsTo(Role, { foreignKey: { allowNull: false } });

Class.belongsTo(Level, { foreignKey: { allowNull: false } });
Class.belongsTo(Tenant, { foreignKey: { allowNull: false } });
Class.belongsTo(Subject, { foreignKey: { allowNull: false } });
Student.belongsTo(Class, { foreignKey: { allowNull: false } });

Student.belongsToMany(Contact, {
    as: 'Contacts',
    through: { model: StudentContact, unique: false },
    foreignKey: 'student_studentId'
});
Contact.belongsToMany(Student, {
    as: 'Students',
    through: { model: StudentContact, unique: false },
    foreignKey: 'contact_contactId'
});

sequelize
    .sync({ force: true })
    .then(result => {
        return Tenant.findByPk(1);
    })
    .then(tenant => {
        if (!tenant) {
            seed();
        }

        app.listen(port, () =>
            console.log(`Example app listening on port ${port}!`)
        );
    })
    .catch(err => console.log(err));

app.get('/', (req, res) => {
    sequelize
        .authenticate()
        .then(() => {
            res.send(`Hello World! Connection has been established successfully.`);
        })
        .catch(err => {
            res.send(`Hello World!  'Unable to connect to the database:' ${err}`);
        });
});

我的学生模型：

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

const Students = sequelize.define('student', {
    studentId: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        allowNull: false,
        primaryKey: true
    }
});

module.exports = Students;

我的联系人模型：

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

const Contacts = sequelize.define('contact', {
    contactId: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        allowNull: false,
        primaryKey: true
    }
});

module.exports = Contacts;

我的StudentContact模型：

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

const StudentContact = sequelize.define('studentContact', {
    id: {
        type: Sequelize.INTEGER,
        autoIncrement: true,
        allowNull: false,
        primaryKey: true
    }
});

module.exports = StudentContact;

它创建的模型：

我也尝试手动设置FK，但也无济于事。 Sequelize的文档仅告诉我使用BelongsToMany，但显然还有更多内容。

https://sequelize.org/master/class/lib/associations/belongs-to-many.js~BelongsToMany.html

Answer 1

不久前，我遇到了类似的问题，也很沮丧，无法从续集文档中找到正确的解决方案。后来，我解决了一个不是最好的解决方案，但对我来说很好用。在StudentContact模型中手动设置两个FK后，可以编写以下两个语句。

StudentContact.belongsTo（Students，{foreignKey：“ id”}）

StudentContact.belongsTo（Contacts，{ForeignKey：“ id”}）;

Answer 2

您只需要像下面这样更改StudentContact的定义：

dopri5

分隔许多关系不会创建关系

2 个答案: