Use ObjectId from MongoDB with mysql - typeorm

Question

Is their any possibility to use mongoDB ObjectID system with MySql and typeORM instead of using an incremental ID?
The goal would be to define my entity like this:
#Entity()
export class RolePermission implements IRolePermission {
#ObjectIdColumn() id?: ObjectID;
#Column()
#IsNotEmpty()
roleId: ObjectID;
#Column()
#IsNotEmpty()
permissionId: ObjectID;
}
My entities could therefore have an ID without even being persisted. The ObjectId system would prevent collisions on the unique constraint I'd like to use for this column.
If a system like that can be implemented, is their any performance downside? I remember implementing such a system with PHP, and at the time, I had read this response that made me think that it was ok: Is there a REAL performance difference between INT and VARCHAR primary keys?

Answer 1

It's in fact really simple. You just need to use the ObjectID object from the mongodb package and declare your entities like you would do usually.
First, install mongodb dependencies:
yarn add mongodb
yarn add #types/mongodb
Then, declare your entity. Here an example with a working relationship between a user and an article:
user.entity.ts:
import { Entity, Column, ManyToOne, PrimaryColumn } from 'typeorm';
import { Article } from './article.entity';
import { ObjectID } from 'mongodb';
#Entity()
export class User {
constructor() {
this.id = (new ObjectID()).toString();
}
#PrimaryColumn()
id: string;
#Column({ length: 500 })
username: string = null;
#OneToMany(type => Article, article => article.user)
articles: Article[];
}
article.entity.ts:
import { Entity, Column, ManyToOne, PrimaryColumn } from 'typeorm';
import { User } from './user.entity';
import { ObjectID } from 'mongodb';
#Entity()
export class Article {
constructor() {
this.id = (new ObjectID()).toString();
}
#PrimaryColumn()
id: string;
#Column({ length: 500 })
title: string = null;
#ManyToOne(type => User, user => user.articles, {nullable: true})
user: User;
}
And use it as you would normally do:
const user = new User();
user.username = 'email#adress.com';
const article = new Article();
article.title = 'Mon titre';
article.user = user;
await this.userRepository.save(user);
await this.articleRepository.save(article);