How to implement many to many association in sequelize

Question

I have two tables: Books and Articles with a many-to-many relationship between them. Joining table is BookArticles.

models/books.js

module.exports =          


        

Answer 1

This is how i solved the similar problem i had two models a user model

var user = sequelize.define('user', {
    name: {
        Sequelize.STRING(255)
    },
    email: {
        type: Sequelize.STRING(255),
        unique: true,
        validate: {
            isEmail: true
        }
    }
});

and a roles model

var Role = sequelize.define('role', {
    name: {
        Sequelize.ENUM('ER', 'ALL', 'DL')
    },
    description: {
        type: Sequelize.TEXT
    }
});

Then i created the union model UserRole

var UserRole = sequelize.define('user_role', {
    id: {
        type: Sequelize.INTEGER,
        primaryKey: true,
        autoIncrement: true
    },
    name: {
        type: Sequelize.ENUM('Admin', 'Staff', 'Customer', 'Owner')
    }
});

Note: you have to explicitly define the id for UserRole otherwise sequelize will use the two foreign keys in this case user_id and role_id as your primary keys.

Then i created the belongs to many relationship as follows

User.belongsToMany(Role, { as: 'Roles', through: { model: UserRole, unique: false }, foreignKey: 'user_id' });
Role.belongsToMany(User, { as: 'Users', through: { model: UserRole, unique: false }, foreignKey: 'role_id' });