Creating Associations with sequelize and mysql - mysql

Question

I am trying to create seqeulize models in nodejs app on mysql db. However, When I run the codes, foreign keys are not being created as intended.
This are my models:
Category Model
"use strict";
module.exports = (sequelize, DataTypes) => {
const Category = sequelize.define("Category", {
category_id: {
type: DataTypes.STRING(255),
unique: true,
primaryKey: true,
},
name: { type: DataTypes.STRING, unique: true, allowNull: false },
slug: { type: DataTypes.STRING, unique: true, allowNull: false },
created_at: {
type: DataTypes.DATE,
defaultValue: sequelize.literal("CURRENT_TIMESTAMP"),
},
updated_at: {
type: DataTypes.DATE,
defaultValue: sequelize.literal(
"CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP"
),
},
});
Category.associate = (models) => {
Category.hasMany(models.Product);
};
return Category;
};
Product Model
"use strict";
module.exports = (sequelize, DataTypes) => {
const Product = sequelize.define("Product", {
product_id: {
type: DataTypes.STRING(255),
allowNull: false,
unique: true,
primaryKey: true,
},
name: {
type: DataTypes.STRING,
allowNull: false,
},
slug: {
type: DataTypes.STRING,
allowNull: false,
unique: true,
},
sku: {
type: DataTypes.STRING,
allowNull: false,
unique: true,
},
short_description: {
type: DataTypes.TEXT,
allowNull: false,
},
description: {
type: DataTypes.TEXT,
allowNull: false,
},
price: {
type: DataTypes.DECIMAL,
allowNull: false,
min: 1,
},
discount: {
type: DataTypes.DECIMAL,
allowNull: true,
},
quantity: {
type: DataTypes.INTEGER,
},
vat: {
type: DataTypes.DECIMAL,
allowNull: true,
},
tags: {
type: DataTypes.STRING(255),
allowNull: true,
},
rate: {
type: DataTypes.INTEGER,
allowNull: true,
},
points: {
type: DataTypes.INTEGER,
allowNull: true,
},
new: {
type: DataTypes.VIRTUAL,
get() {
var msPerDay = 8.64e7;
// Copy dates so don't mess them up
var x0 = new Date(this.getDataValue("created_at"));
var x1 = new Date();
// Set to noon - avoid DST errors
x0.setHours(12, 0, 0);
x1.setHours(12, 0, 0);
// Round to remove daylight saving errors
return Math.round((x1 - x0) / msPerDay) <= 30;
},
set(value) {
throw new Error("Can't set Product.new property.");
},
},
thumb_image: {
type: DataTypes.STRING,
allowNull: true,
get() {
if (this.getDataValue("thumb_image")) {
return JSON.parse(this.getDataValue("thumb_image"));
}
return [];
},
set(val) {
this.setDataValue("thumbImage", JSON.stringify(val));
},
},
images: {
type: DataTypes.STRING,
allowNull: true,
get() {
if (this.getDataValue("images")) {
return JSON.parse(this.getDataValue("images"));
}
return [];
},
set(val) {
this.setDataValue("images", JSON.stringify(val));
},
},
featured: {
type: DataTypes.BOOLEAN,
defaultValue: false,
},
created_at: {
type: DataTypes.DATE,
defaultValue: sequelize.literal("CURRENT_TIMESTAMP"),
},
updated_at: {
type: DataTypes.DATE,
defaultValue: sequelize.literal(
"CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP"
),
},
});
Product.associate = (models) => {
Product.belongsTo(models.Category, {
foreignKey: "category_id",
});
Product.belongsTo(models.Brand, {
foreignKey: "brand_id",
});
Product.belongsTo(models.CartItem, {
foreignKey: "cart_id",
});
};
return Product;
};
Brand Model
"use strict";
module.exports = (sequelize, DataTypes) => {
const Brand = sequelize.define("Brand", {
brand_id: {
type: DataTypes.STRING(255),
unique: true,
primaryKey: true,
},
name: { type: DataTypes.STRING, unique: true, allowNull: false },
slug: { type: DataTypes.STRING, unique: true, allowNull: false },
created_at: {
type: DataTypes.DATE,
defaultValue: sequelize.literal("CURRENT_TIMESTAMP"),
},
updated_at: {
type: DataTypes.DATE,
defaultValue: sequelize.literal(
"CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP"
),
},
});
Brand.associate = (models) => {
Brand.hasMany(models.Product);
};
return Brand;
};
And these is my Models/index.js file
/* eslint-disable no-undef */
"use strict";
const fs = require("fs");
const path = require("path");
const Sequelize = require("sequelize");
const basename = path.basename(__filename);
const env = process.env.NODE_ENV || "development";
const config = require(__dirname + "/../../config/config.js")[env];
const db = {};
let sequelize;
if (config.use_env_variable) {
sequelize = new Sequelize(process.env[config.use_env_variable], config);
} else {
sequelize = new Sequelize(
config.database,
config.username,
config.password,
config
);
}
db.sequelize = sequelize;
db.Sequelize = Sequelize;
fs.readdirSync(__dirname)
.filter((file) => {
return (
file.indexOf(".") !== 0 && file !== basename && file.slice(-3) === ".js"
);
})
.forEach((file) => {
const model = require(path.join(__dirname, file))(
sequelize,
Sequelize.DataTypes
);
db[model.name] = model;
});
Object.keys(db).forEach((modelName) => {
if (db[modelName].associate) {
db[modelName].associate(db);
}
});
db.sequelize
.sync({ force: process.env.NODE_ENV === "development" })
.then(() => {
console.log("Drop and re-sync db.");
});
module.exports = db;
Now when I run the server, I expected the products table to have the fields category_id and brand_id. However, am getting additional fields brand_brand_id and category_category_id on the products table.
Besides, I cannot retrieve the categories, brands and products with the include properties when fecthing data.
What I want is to have the products table properly created in the database with the required foreign keys

Answer 1

Since you have customized foreign keys you have to indicate them in both paired associations:
Category.associate = (models) => {
Category.hasMany(models.Product, { foreignKey: "category_id" });
};
Product.associate = (models) => {
Product.belongsTo(models.Category, {
foreignKey: "category_id",
});
Product.belongsTo(models.Brand, {
foreignKey: "brand_id",
});
Product.belongsTo(models.CartItem, {
foreignKey: "cart_id",
});
};
Brand.associate = (models) => {
Brand.hasMany(models.Product, { foreignKey: "brand_id" });
};