npm install @mikro-orm/core @mikro-orm/postgresql    # PostgreSQL
npm install @mikro-orm/core @mikro-orm/mysql          # MySQL
npm install @mikro-orm/core @mikro-orm/mariadb        # MariaDB
npm install @mikro-orm/core @mikro-orm/sqlite         # SQLite
npm install @mikro-orm/core @mikro-orm/libsql         # libSQL / Turso
npm install @mikro-orm/core @mikro-orm/mongodb        # MongoDB
npm install @mikro-orm/core @mikro-orm/mssql          # MS SQL Server
npm install @mikro-orm/core @mikro-orm/oracledb       # Oracle

import { defineEntity, p, MikroORM } from '@mikro-orm/postgresql';

const AuthorSchema = defineEntity({
  name: 'Author',
  properties: {
    id: p.integer().primary(),
    name: p.string(),
    email: p.string(),
    books: () => p.oneToMany(Book).mappedBy('author'),
  },
});
export class Author extends AuthorSchema.class {}
AuthorSchema.setClass(Author);

const BookSchema = defineEntity({
  name: 'Book',
  properties: {
    id: p.integer().primary(),
    title: p.string(),
    author: () => p.manyToOne(Author).inversedBy('books'),
  },
});
export class Book extends BookSchema.class {}
BookSchema.setClass(Book);

// Initialize the ORM
const orm = await MikroORM.init({
  entities: [Author, Book],
  dbName: 'my-db',
});

// Create and persist entities
const author = orm.em.create(Author, { name: 'Jon Snow', email: '[email protected]' });
orm.em.create(Book, { title: 'My Life on The Wall', author });
await orm.em.flush();

// Find entities with relations
const authors = await orm.em.find(
  Author,
  { name: { $like: '%Jon%' } },
  {
    populate: ['books'],
  },
);