Database Access with TypeORM

Install

npm i typeorm reflect-metadata sqlite3
npm i -D @types/node

Add import 'reflect-metadata'; once.

Entity definition

import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm';

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

  @Column({ length: 100 })
  name!: string;

  @Column({ type: 'int', nullable: true })
  age?: number;
}

DataSource (connection) setup

import { DataSource } from 'typeorm';
import { User } from './entity/User';

export const AppDataSource = new DataSource({
  type: 'sqlite',
  database: 'dev.db',
  synchronize: true, // auto‑create tables (dev only)
  entities: [User],
});

await AppDataSource.initialize();

Repository usage

const repo = AppDataSource.getRepository(User);
await repo.save({ name: 'Alice', age: 30 });
const all = await repo.find();