12 · TypeORM (Entities + Migrations)

• Explicit entities + repositories; migrations-first in prod.
• Great for long-lived schemas and SQL-heavy workflows.

npm install typeorm reflect-metadata sqlite3

import "reflect-metadata";
import { DataSource } from "typeorm";
import { User } from "@/entities/User";
import { Post } from "@/entities/Post";

export const AppDataSource = new DataSource({
  type: "sqlite",
  database: "dev.db",
  synchronize: true, // dev only
  entities: [User, Post],
});

// entities/User.ts
import { Entity, PrimaryGeneratedColumn, Column, OneToMany } from "typeorm";
import { Post } from "./Post";

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id: number;

  @Column({ unique: true })
  email: string;

  @OneToMany(() => Post, (post) => post.author)
  posts: Post[];
}

await AppDataSource.initialize();
const repo = AppDataSource.getRepository(User);
await repo.find({ relations: ["posts"] });

• Set type: "postgres", url: process.env.DATABASE_URL.
• Use migrations (typeorm migration:generate/run) instead of synchronize in prod.